diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9cd3cf47..0456a293 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,13 +24,13 @@ set(CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake/")
 set(MMC_SRC "${PROJECT_SOURCE_DIR}")
 set(MMC_BIN "${PROJECT_BINARY_DIR}")
 
-# Output all executables and shared libs in the main build folder, not in subfolders.
-set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR})
-if(UNIX)
-	set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR})
-endif()
+# # Output all executables and shared libs in the main build folder, not in subfolders.
+# set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR})
+# if(UNIX)
+# 	set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR})
+# endif()
 
-set(CMAKE_JAVA_TARGET_OUTPUT_DIR ${PROJECT_BINARY_DIR}/jars)
+set(CMAKE_JAVA_TARGET_OUTPUT_DIR ${PROJECT_BINARY_DIR}/application/jars)
 
 ######## Set compiler flags ########
 set(CMAKE_CXX_STANDARD_REQUIRED true)
diff --git a/application/pages/ModFolderPage.cpp b/application/pages/ModFolderPage.cpp
index bbe16671..cef4ed73 100644
--- a/application/pages/ModFolderPage.cpp
+++ b/application/pages/ModFolderPage.cpp
@@ -47,8 +47,7 @@ ModFolderPage::ModFolderPage(BaseInstance *inst, std::shared_ptr<ModList> mods,
 	ui->modTreeView->setModel(m_mods.get());
 	ui->modTreeView->installEventFilter(this);
 	auto smodel = ui->modTreeView->selectionModel();
-	connect(smodel, SIGNAL(currentChanged(QModelIndex, QModelIndex)),
-			SLOT(modCurrent(QModelIndex, QModelIndex)));
+	connect(smodel, &QItemSelectionModel::currentChanged, this, &ModFolderPage::modCurrent);
 }
 
 void ModFolderPage::opened()
@@ -91,7 +90,15 @@ bool CoreModFolderPage::shouldDisplay() const
 		auto version = inst->getMinecraftProfile();
 		if (!version)
 			return true;
-		if (version->m_releaseTime < g_VersionFilterData.legacyCutoffDate)
+		if(!version->versionPatch("net.minecraftforge"))
+		{
+			return false;
+		}
+		if(!version->versionPatch("net.minecraft"))
+		{
+			return false;
+		}
+		if(version->versionPatch("net.minecraft")->getReleaseDateTime() < g_VersionFilterData.legacyCutoffDate)
 		{
 			return true;
 		}
diff --git a/application/pages/VersionPage.cpp b/application/pages/VersionPage.cpp
index 42e4a9bf..137abcfc 100644
--- a/application/pages/VersionPage.cpp
+++ b/application/pages/VersionPage.cpp
@@ -156,10 +156,10 @@ void VersionPage::packageCurrent(const QModelIndex &current, const QModelIndex &
 	switch(severity)
 	{
 		case PROBLEM_WARNING:
-			ui->frame->setModText(tr("%1 possibly has issues.").arg(patch->getPatchName()));
+			ui->frame->setModText(tr("%1 possibly has issues.").arg(patch->getName()));
 			break;
 		case PROBLEM_ERROR:
-			ui->frame->setModText(tr("%1 has issues!").arg(patch->getPatchName()));
+			ui->frame->setModText(tr("%1 has issues!").arg(patch->getName()));
 			break;
 		default:
 		case PROBLEM_NONE:
@@ -251,8 +251,7 @@ void VersionPage::on_modBtn_clicked()
 void VersionPage::on_jarmodBtn_clicked()
 {
 	bool nagShown = false;
-	auto traits = m_version->traits;
-	if (!traits.contains("legacyLaunch") && !traits.contains("alphaLaunch"))
+	if (!m_version->hasTrait("legacyLaunch") && !m_version->hasTrait("alphaLaunch"))
 	{
 		// not legacy launch... nag
 		auto seenNag = MMC->settings()->get("JarModNagSeen").toBool();
@@ -513,7 +512,7 @@ void VersionPage::on_editBtn_clicked()
 	{
 		return;
 	}
-	auto filename = version->getPatchFilename();
+	auto filename = version->getFilename();
 	if(!QFileInfo::exists(filename))
 	{
 		qWarning() << "file" << filename << "can't be opened for editing, doesn't exist!";
diff --git a/application/resources/versions/minecraft.json b/application/resources/versions/minecraft.json
index 58b153c2..9c08a83f 100644
--- a/application/resources/versions/minecraft.json
+++ b/application/resources/versions/minecraft.json
@@ -5,7 +5,6 @@
 		"checksum": "6897c3287fb971c9f362eb3ab20f5ddd",
 		"releaseTime": "2013-04-25T17:45:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -13,7 +12,6 @@
 		"checksum": "5c1219d869b87d233de3033688ec7567",
 		"releaseTime": "2013-03-20T12:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -21,7 +19,6 @@
 		"checksum": "fd11cbc5b01aae1d62cff0145171f3d9",
 		"releaseTime": "2013-03-07T00:00:00+02:00",
 		"type": "snapshot",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -29,7 +26,6 @@
 		"checksum": "8e80fb01b321c6b3c7efca397a3eea35",
 		"releaseTime": "2012-12-28T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -37,7 +33,6 @@
 		"checksum": "48677dc4c2b98c29918722b5ab27b4fd",
 		"releaseTime": "2012-12-20T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -45,7 +40,6 @@
 		"checksum": "b15e2b2b6b4629f0d99a95b6b44412a0",
 		"releaseTime": "2012-11-20T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -53,7 +47,6 @@
 		"checksum": "7aa46c8058cba2f38e9d2ddddcc77c72",
 		"releaseTime": "2012-11-14T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -61,7 +54,6 @@
 		"checksum": "9cc3295931edb6339f22989fe1b612a6",
 		"releaseTime": "2012-11-01T00:00:00+02:00",
 		"type": "snapshot",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -69,7 +61,6 @@
 		"checksum": "771175c01778ea67395bc6919a5a9dc5",
 		"releaseTime": "2012-10-25T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -77,7 +68,6 @@
 		"checksum": "542621a5298659dc65f383f35170fc4c",
 		"releaseTime": "2012-10-23T00:00:00+02:00",
 		"type": "snapshot",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -85,7 +75,6 @@
 		"checksum": "32a654388b54d3e4bb29c1a46e7d6a12",
 		"releaseTime": "2012-10-19T00:00:00+02:00",
 		"type": "snapshot",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -93,7 +82,6 @@
 		"checksum": "969699f13e5bbe7f12e40ac4f32b7d9a",
 		"releaseTime": "2012-08-16T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -101,7 +89,6 @@
 		"checksum": "266ccbc9798afd2eadf3d6c01b4c562a",
 		"releaseTime": "2012-08-01T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -109,7 +96,6 @@
 		"checksum": "a6effac1eaccf5d429aae340cf95ed5d",
 		"releaseTime": "2012-07-26T00:00:00+02:00",
 		"type": "snapshot",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -117,7 +103,6 @@
 		"checksum": "8e8778078a175a33603a585257f28563",
 		"releaseTime": "2012-03-30T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -125,7 +110,6 @@
 		"checksum": "25423eab6d8707f96cc6ad8a21a7250a",
 		"releaseTime": "2012-03-22T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -133,7 +117,6 @@
 		"checksum": "12f6c4b1bdcc63f029e3c088a364b8e4",
 		"releaseTime": "2012-03-02T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -141,7 +124,6 @@
 		"checksum": "6189e96efaea11e5164b4a4755574324",
 		"releaseTime": "2012-03-01T00:00:01+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -149,7 +131,6 @@
 		"checksum": "97067a603eba2b6eb75d3194f81f6bcd",
 		"releaseTime": "2012-03-01T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -157,7 +138,6 @@
 		"checksum": "e92302d2acdba7c97e0d8df1e10d2006",
 		"releaseTime": "2012-01-12T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -165,7 +145,6 @@
 		"checksum": "3820d222b95d0b8c520d9596a756a6e6",
 		"releaseTime": "2011-11-18T00:00:00+02:00",
 		"type": "release",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -173,7 +152,6 @@
 		"checksum": "f8c5a2ccd3bc996792bbe436d8cc08bc",
 		"releaseTime": "2011-09-19T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -181,7 +159,6 @@
 		"checksum": "a59a9fd4c726a573b0a2bdd10d857f59",
 		"releaseTime": "2011-09-15T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -189,7 +166,6 @@
 		"checksum": "eae3353fdaa7e10a59b4cb5b45bfa10d",
 		"releaseTime": "2011-07-08T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -197,7 +173,6 @@
 		"checksum": "dd9215ab1141170d4871f42bff4ab302",
 		"releaseTime": "2011-07-01T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -205,7 +180,6 @@
 		"checksum": "682419e9ed1a236c3067822d53cda1e4",
 		"releaseTime": "2011-06-30T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -213,7 +187,6 @@
 		"checksum": "ce80072464433cd5b05d505aa8ff29d1",
 		"releaseTime": "2011-05-31T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -221,7 +194,6 @@
 		"checksum": "2aba888864b32038c8d22ee5df71b7c8",
 		"releaseTime": "2011-05-28T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -229,7 +201,6 @@
 		"checksum": "5c4df6f120336f113180698613853dba",
 		"releaseTime": "2011-05-26T00:00:04+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -237,7 +208,6 @@
 		"checksum": "efc2becca965e4f8feb5b4210c6a4fd1",
 		"releaseTime": "2011-05-26T00:00:03+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -245,7 +215,6 @@
 		"checksum": "01330b1c930102a683a4dd8d792e632e",
 		"releaseTime": "2011-05-26T00:00:02+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -253,7 +222,6 @@
 		"checksum": "a7e82c441a57ef4068c533f4d777336a",
 		"releaseTime": "2011-05-26T00:00:01+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -261,7 +229,6 @@
 		"checksum": "d531e221227a65392259d3141893280d",
 		"releaseTime": "2011-05-26T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -269,7 +236,6 @@
 		"checksum": "d02fa9998e30693d8d989d5f88cf0040",
 		"releaseTime": "2011-04-20T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -277,7 +243,6 @@
 		"checksum": "24289130902822d73f8722b52bc07cdb",
 		"releaseTime": "2011-04-19T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -285,7 +250,6 @@
 		"checksum": "9379e54b581ba4ef3acc3e326e87db91",
 		"releaseTime": "2011-04-05T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -293,7 +257,6 @@
 		"checksum": "71e64b61175b371ed148b385f2d14ebf",
 		"releaseTime": "2011-03-31T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -301,7 +264,6 @@
 		"checksum": "4203826f35e1036f089919032c3d19d1",
 		"releaseTime": "2011-02-23T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -309,7 +271,6 @@
 		"checksum": "de2164df461d028229ed2e101181bbd4",
 		"releaseTime": "2011-02-22T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -317,7 +278,6 @@
 		"checksum": "1736c5ba4f63a981220c2a18a4120180",
 		"releaseTime": "2011-01-21T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -325,7 +285,6 @@
 		"checksum": "486d83ec00554b45ffa21af2faa0116a",
 		"releaseTime": "2011-01-14T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -333,7 +292,6 @@
 		"checksum": "6426223efe23c3931a4ef89685be3349",
 		"releaseTime": "2011-01-13T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -341,7 +299,6 @@
 		"checksum": "7d547e495a770c62054ef136add43034",
 		"releaseTime": "2010-12-22T00:00:01+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -349,7 +306,6 @@
 		"checksum": "1f9331f2bfca81b6ce2acdfc1f105837",
 		"releaseTime": "2010-12-22T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -357,7 +313,6 @@
 		"checksum": "d200c465b8c167cc8df6537531fc9a48",
 		"releaseTime": "2010-12-21T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -365,7 +320,6 @@
 		"checksum": "03bd20b870dbbd121de5dca98af4e1ce",
 		"releaseTime": "2010-12-20T00:00:01+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -373,7 +327,6 @@
 		"checksum": "5f8733dbbf09b4e7c874661a3c29c239",
 		"releaseTime": "2010-12-20T00:00:00+02:00",
 		"type": "old_beta",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -381,7 +334,6 @@
 		"checksum": "ddd5e39467f28d1ea1a03b4d9e790867",
 		"releaseTime": "2010-12-03T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -389,7 +341,6 @@
 		"checksum": "7d3a43037190970ff2e11153b5718b74",
 		"releaseTime": "2010-12-01T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -397,7 +348,6 @@
 		"checksum": "0a1cc8c668faa6dc93fc418e8b4b097a",
 		"releaseTime": "2010-11-30T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -405,7 +355,6 @@
 		"checksum": "b2c25a753c82a1cd228ce71469829dc1",
 		"releaseTime": "2010-11-26T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -413,7 +362,6 @@
 		"checksum": "3ad4808ef2ac3b65d10305315260da03",
 		"releaseTime": "2010-11-25T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -421,7 +369,6 @@
 		"checksum": "70cbab762b17c5b11fefea9b12564119",
 		"releaseTime": "2010-11-24T00:00:01+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -429,7 +376,6 @@
 		"checksum": "25f053114e34b915e675f82d58f08711",
 		"releaseTime": "2010-11-24T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -437,7 +383,6 @@
 		"checksum": "6250fb17f8898c4d970d6bd03c229177",
 		"releaseTime": "2010-11-10T00:00:01+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -445,7 +390,6 @@
 		"checksum": "0f9fe018b344fd9dd849005f9bdca803",
 		"releaseTime": "2010-11-10T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "texturepacks"]
 	},
 	{
@@ -453,7 +397,6 @@
 		"checksum": "0a496e44a7b4e2f493b5893d8e5845bd",
 		"releaseTime": "2010-11-05T00:00:01+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -461,7 +404,6 @@
 		"checksum": "0a496e44a7b4e2f493b5893d8e5845bd",
 		"releaseTime": "2010-11-05T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -469,7 +411,6 @@
 		"checksum": "f5bcb4d0c0e78bc220f164b89ae9bd60",
 		"releaseTime": "2010-11-04T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -477,7 +418,6 @@
 		"checksum": "b2e9333e967cb89488884c2e5c715d4f",
 		"releaseTime": "2010-10-31T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -485,7 +425,6 @@
 		"checksum": "44c384dae02390f700458b95d82c3e2a",
 		"releaseTime": "2010-10-30T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -493,7 +432,6 @@
 		"checksum": "94346e1b8f6ad0e4a284314f0e29207b",
 		"releaseTime": "2010-09-23T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -501,7 +439,6 @@
 		"checksum": "72ba1f834327805cb44164a42b331522",
 		"releaseTime": "2010-09-20T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -509,7 +446,6 @@
 		"checksum": "891fd93e04f5daaf35d73c58e45c01b1",
 		"releaseTime": "2010-09-13T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -517,7 +453,6 @@
 		"checksum": "16ed7dc58244772847991e504afcf02f",
 		"releaseTime": "2010-08-23T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -525,7 +460,6 @@
 		"checksum": "d89760b0871ef61a55c9f336c0439d58",
 		"releaseTime": "2010-08-20T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -533,7 +467,6 @@
 		"checksum": "6bbde02c13aed5766275f4398ede6aae",
 		"releaseTime": "2010-08-12T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -541,7 +474,6 @@
 		"checksum": "ade257d2080d56fa983763f9c701fa14",
 		"releaseTime": "2010-08-04T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -549,7 +481,6 @@
 		"checksum": "227d0c6fa896a231de6269a074c9a458",
 		"releaseTime": "2010-07-30T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -557,7 +488,6 @@
 		"checksum": "6f1b1dd157fa0df39760f5be3eab01b0",
 		"releaseTime": "2010-07-23T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
 	{
@@ -565,7 +495,6 @@
 		"checksum": "ae5f606caa18222e7568819c910ee423",
 		"releaseTime": "2010-07-13T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "y",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
@@ -574,7 +503,6 @@
 		"checksum": "13ce7935c3670e7494e26b2704bfa3e9",
 		"releaseTime": "2010-07-09T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "ax",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
 	},
@@ -583,7 +511,6 @@
 		"checksum": "f5f5aa34760facc10486e906a7c60196",
 		"releaseTime": "2010-06-16T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "net.minecraft.client.d",
 		"appletClass": "net.minecraft.client.MinecraftApplet",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
@@ -593,7 +520,6 @@
 		"checksum": "fcfd7f83a6b27503cf48202381a5adf2",
 		"releaseTime": "2009-12-22T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "com.mojang.minecraft.l",
 		"appletClass": "com.mojang.minecraft.MinecraftApplet",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
@@ -603,7 +529,6 @@
 		"checksum": "a9527cb5aef198e0f53e235ebe13dc75",
 		"releaseTime": "2009-05-22T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "com.mojang.minecraft.c",
 		"appletClass": "com.mojang.minecraft.MinecraftApplet",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
@@ -613,7 +538,6 @@
 		"checksum": "3617fbf5fbfd2b837ebf5ceb63584908",
 		"releaseTime": "2009-05-31T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "com.mojang.minecraft.Minecraft",
 		"appletClass": "com.mojang.minecraft.MinecraftApplet",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
@@ -623,7 +547,6 @@
 		"checksum": "a6e03c2eaf74709facc0d2477648e999",
 		"releaseTime": "2009-05-17T00:00:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "com.mojang.minecraft.Minecraft",
 		"appletClass": "com.mojang.minecraft.MinecraftApplet",
 		"+traits": ["legacyLaunch", "no-texturepacks"]
@@ -633,7 +556,6 @@
 		"checksum": "80882b8936a5c8d91500838a6660b504",
 		"releaseTime": "2009-05-16T13:48:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "com.mojang.minecraft.RubyDung",
 		"+traits": ["no-texturepacks"]
 	},
@@ -642,7 +564,6 @@
 		"checksum": "24c5cc99a2a612697ed2f7d5d04242fe",
 		"releaseTime": "2009-05-16T00:52:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "com.mojang.rubydung.RubyDung",
 		"+traits": ["no-texturepacks"]
 	},
@@ -651,7 +572,6 @@
 		"checksum": "70e33a81c541b13a477e68c1207124eb",
 		"releaseTime": "2009-05-13T23:28:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "com.mojang.rubydung.RubyDung",
 		"+traits": ["no-texturepacks"]
 	},
@@ -660,7 +580,6 @@
 		"checksum": "99fdaea10c494b9c3c3254636b98b799",
 		"releaseTime": "2009-05-13T22:11:00+02:00",
 		"type": "old_alpha",
-		"processArguments": "legacy",
 		"mainClass": "com.mojang.rubydung.RubyDung",
 		"+traits": ["no-texturepacks"]
 	}
diff --git a/logic/CMakeLists.txt b/logic/CMakeLists.txt
index 28c1b8fc..b8c36794 100644
--- a/logic/CMakeLists.txt
+++ b/logic/CMakeLists.txt
@@ -202,7 +202,6 @@ set(LOGIC_SOURCES
 	minecraft/VersionFile.cpp
 	minecraft/VersionFile.h
 	minecraft/ProfilePatch.h
-	minecraft/VersionSource.h
 	minecraft/VersionFilterData.h
 	minecraft/VersionFilterData.cpp
 	minecraft/Mod.h
diff --git a/logic/minecraft/Library.h b/logic/minecraft/Library.h
index 891601be..35b5cb99 100644
--- a/logic/minecraft/Library.h
+++ b/logic/minecraft/Library.h
@@ -13,7 +13,7 @@
 #include "GradleSpecifier.h"
 #include "net/URLConstants.h"
 
-class MojangLibraryDownloadInfo;
+struct MojangLibraryDownloadInfo;
 class Library;
 
 typedef std::shared_ptr<Library> LibraryPtr;
diff --git a/logic/minecraft/MinecraftProfile.cpp b/logic/minecraft/MinecraftProfile.cpp
index 0cf8b548..7586c156 100644
--- a/logic/minecraft/MinecraftProfile.cpp
+++ b/logic/minecraft/MinecraftProfile.cpp
@@ -14,6 +14,7 @@
  */
 
 #include <QFile>
+#include <Version.h>
 #include <QDir>
 #include <QJsonDocument>
 #include <QJsonArray>
@@ -60,11 +61,8 @@ void MinecraftProfile::reload()
 void MinecraftProfile::clear()
 {
 	id.clear();
-	m_updateTime = QDateTime();
-	m_releaseTime = QDateTime();
 	type.clear();
 	assets.clear();
-	processArguments.clear();
 	minecraftArguments.clear();
 	mainClass.clear();
 	appletClass.clear();
@@ -94,13 +92,13 @@ bool MinecraftProfile::remove(const int index)
 	auto patch = versionPatch(index);
 	if (!patch->isRemovable())
 	{
-		qDebug() << "Patch" << patch->getPatchID() << "is non-removable";
+		qDebug() << "Patch" << patch->getID() << "is non-removable";
 		return false;
 	}
 
 	if(!m_strategy->removePatch(patch))
 	{
-		qCritical() << "Patch" << patch->getPatchID() << "could not be removed";
+		qCritical() << "Patch" << patch->getID() << "could not be removed";
 		return false;
 	}
 
@@ -117,7 +115,7 @@ bool MinecraftProfile::remove(const QString id)
 	int i = 0;
 	for (auto patch : VersionPatches)
 	{
-		if (patch->getPatchID() == id)
+		if (patch->getID() == id)
 		{
 			return remove(i);
 		}
@@ -131,12 +129,12 @@ bool MinecraftProfile::customize(int index)
 	auto patch = versionPatch(index);
 	if (!patch->isCustomizable())
 	{
-		qDebug() << "Patch" << patch->getPatchID() << "is not customizable";
+		qDebug() << "Patch" << patch->getID() << "is not customizable";
 		return false;
 	}
 	if(!m_strategy->customizePatch(patch))
 	{
-		qCritical() << "Patch" << patch->getPatchID() << "could not be customized";
+		qCritical() << "Patch" << patch->getID() << "could not be customized";
 		return false;
 	}
 	reapplySafe();
@@ -151,12 +149,12 @@ bool MinecraftProfile::revertToBase(int index)
 	auto patch = versionPatch(index);
 	if (!patch->isRevertible())
 	{
-		qDebug() << "Patch" << patch->getPatchID() << "is not revertible";
+		qDebug() << "Patch" << patch->getID() << "is not revertible";
 		return false;
 	}
 	if(!m_strategy->revertPatch(patch))
 	{
-		qCritical() << "Patch" << patch->getPatchID() << "could not be reverted";
+		qCritical() << "Patch" << patch->getID() << "could not be reverted";
 		return false;
 	}
 	reapplySafe();
@@ -172,14 +170,14 @@ QString MinecraftProfile::versionFileId(const int index) const
 	{
 		return QString();
 	}
-	return VersionPatches.at(index)->getPatchID();
+	return VersionPatches.at(index)->getID();
 }
 
 ProfilePatchPtr MinecraftProfile::versionPatch(const QString &id)
 {
 	for (auto file : VersionPatches)
 	{
-		if (file->getPatchID() == id)
+		if (file->getID() == id)
 		{
 			return file;
 		}
@@ -216,9 +214,9 @@ bool MinecraftProfile::revertToVanilla()
 		}
 		if(it->isRevertible() || it->isRemovable())
 		{
-			if(!remove(it->getPatchID()))
+			if(!remove(it->getID()))
 			{
-				qWarning() << "Couldn't remove" << it->getPatchID() << "from profile!";
+				qWarning() << "Couldn't remove" << it->getID() << "from profile!";
 				reapplySafe();
 				saveCurrentOrder();
 				return false;
@@ -230,7 +228,7 @@ bool MinecraftProfile::revertToVanilla()
 	return true;
 }
 
-QList<std::shared_ptr<Library> > MinecraftProfile::getActiveNormalLibs()
+QList<std::shared_ptr<Library> > MinecraftProfile::getActiveNormalLibs() const
 {
 	QList<std::shared_ptr<Library> > output;
 	for (auto lib : libraries)
@@ -251,7 +249,7 @@ QList<std::shared_ptr<Library> > MinecraftProfile::getActiveNormalLibs()
 	return output;
 }
 
-QList<std::shared_ptr<Library> > MinecraftProfile::getActiveNativeLibs()
+QList<std::shared_ptr<Library> > MinecraftProfile::getActiveNativeLibs() const
 {
 	QList<std::shared_ptr<Library> > output;
 	for (auto lib : libraries)
@@ -282,16 +280,16 @@ QVariant MinecraftProfile::data(const QModelIndex &index, int role) const
 		switch (column)
 		{
 		case 0:
-			return VersionPatches.at(row)->getPatchName();
+			return VersionPatches.at(row)->getName();
 		case 1:
 		{
 			if(patch->isCustom())
 			{
-				return QString("%1 (Custom)").arg(patch->getPatchVersion());
+				return QString("%1 (Custom)").arg(patch->getVersion());
 			}
 			else
 			{
-				return patch->getPatchVersion();
+				return patch->getVersion();
 			}
 		}
 		default:
@@ -366,7 +364,7 @@ void MinecraftProfile::saveCurrentOrder() const
 	{
 		if(!item->isMoveable())
 			continue;
-		order.append(item->getPatchID());
+		order.append(item->getID());
 	}
 	m_strategy->saveOrder(order);
 }
@@ -419,7 +417,6 @@ void MinecraftProfile::reapply()
 	{
 		file->applyTo(this);
 	}
-	finalize();
 }
 
 bool MinecraftProfile::reapplySafe()
@@ -437,41 +434,186 @@ bool MinecraftProfile::reapplySafe()
 	return true;
 }
 
-void MinecraftProfile::finalize()
+static void applyString(const QString & from, QString & to)
+{
+	if(from.isEmpty())
+		return;
+	to = from;
+}
+
+void MinecraftProfile::applyMinecraftVersion(const QString& id)
+{
+	applyString(id, this->id);
+}
+
+void MinecraftProfile::applyAppletClass(const QString& appletClass)
+{
+	applyString(appletClass, this->appletClass);
+}
+
+void MinecraftProfile::applyMainClass(const QString& mainClass)
+{
+	applyString(mainClass, this->mainClass);
+}
+
+void MinecraftProfile::applyMinecraftArguments(const QString& minecraftArguments, bool isMinecraft)
+{
+	applyString(minecraftArguments, this->minecraftArguments);
+	if(isMinecraft)
+	{
+		applyString(minecraftArguments, this->vanillaMinecraftArguments);
+	}
+}
+
+void MinecraftProfile::applyMinecraftVersionType(const QString& type)
+{
+	applyString(type, this->type);
+}
+
+void MinecraftProfile::applyMinecraftAssets(const QString& assets)
+{
+	applyString(assets, this->assets);
+}
+
+void MinecraftProfile::applyTraits(const QSet<QString>& traits)
+{
+	this->traits.unite(traits);
+}
+
+void MinecraftProfile::applyTweakers(const QStringList& tweakers)
+{
+	// FIXME: check for dupes?
+	// FIXME: does order matter?
+	for (auto tweaker : tweakers)
+	{
+		this->tweakers += tweaker;
+	}
+}
+
+void MinecraftProfile::applyJarMods(const QList<JarmodPtr>& jarMods)
+{
+	this->jarMods.append(jarMods);
+}
+
+static int findLibraryByName(QList<LibraryPtr> haystack, const GradleSpecifier &needle)
+{
+	int retval = -1;
+	for (int i = 0; i < haystack.size(); ++i)
+	{
+		if (haystack.at(i)->rawName().matchName(needle))
+		{
+			// only one is allowed.
+			if (retval != -1)
+				return -1;
+			retval = i;
+		}
+	}
+	return retval;
+}
+
+void MinecraftProfile::applyLibrary(LibraryPtr library, bool isMinecraft)
+{
+	auto insert = [&](QList<LibraryPtr> & into)
+	{
+		// find the library by name.
+		const int index = findLibraryByName(into, library->rawName());
+		// library not found? just add it.
+		if (index < 0)
+		{
+			into.append(Library::limitedCopy(library));
+			return;
+		}
+		auto existingLibrary = into.at(index);
+		// if we are higher it means we should update
+		if (Version(library->version()) > Version(existingLibrary->version()))
+		{
+			auto libraryCopy = Library::limitedCopy(library);
+			into.replace(index, libraryCopy);
+		}
+	};
+	insert(libraries);
+	if(isMinecraft)
+	{
+		insert(vanillaLibraries);
+	}
+}
+
+
+QString MinecraftProfile::getMinecraftVersion() const
+{
+	return id;
+}
+
+QString MinecraftProfile::getAppletClass() const
+{
+	return appletClass;
+}
+
+QString MinecraftProfile::getMainClass() const
+{
+	return mainClass;
+}
+
+const QSet<QString> &MinecraftProfile::getTraits() const
+{
+	return traits;
+}
+
+const QStringList & MinecraftProfile::getTweakers() const
+{
+	return tweakers;
+}
+
+bool MinecraftProfile::hasTrait(const QString& trait) const
+{
+	return traits.contains(trait);
+}
+
+
+QString MinecraftProfile::getMinecraftVersionType() const
+{
+	return type;
+}
+
+QString MinecraftProfile::getMinecraftAssets() const
 {
 	// HACK: deny april fools. my head hurts enough already.
 	QDate now = QDate::currentDate();
 	bool isAprilFools = now.month() == 4 && now.day() == 1;
 	if (assets.endsWith("_af") && !isAprilFools)
 	{
-		assets = assets.left(assets.length() - 3);
+		return assets.left(assets.length() - 3);
 	}
 	if (assets.isEmpty())
 	{
-		assets = "legacy";
+		return QLatin1Literal("legacy");
 	}
-	auto finalizeArguments = [&]( QString & minecraftArguments, const QString & processArguments ) -> void
-	{
-		if (!minecraftArguments.isEmpty())
-			return;
-		QString toCompare = processArguments.toLower();
-		if (toCompare == "legacy")
-		{
-			minecraftArguments = " ${auth_player_name} ${auth_session}";
-		}
-		else if (toCompare == "username_session")
-		{
-			minecraftArguments = "--username ${auth_player_name} --session ${auth_session}";
-		}
-		else if (toCompare == "username_session_version")
-		{
-			minecraftArguments = "--username ${auth_player_name} "
-								"--session ${auth_session} "
-								"--version ${profile_name}";
-		}
-	};
-	finalizeArguments(vanillaMinecraftArguments, vanillaProcessArguments);
-	finalizeArguments(minecraftArguments, processArguments);
+	return assets;
+}
+
+QString MinecraftProfile::getMinecraftArguments() const
+{
+	return minecraftArguments;
+}
+
+QString MinecraftProfile::getVanillaMinecraftArguments() const
+{
+	return vanillaMinecraftArguments;
+}
+
+const QList<JarmodPtr> & MinecraftProfile::getJarMods() const
+{
+	return jarMods;
+}
+
+const QList<LibraryPtr> & MinecraftProfile::getLibraries() const
+{
+	return libraries;
+}
+
+const QList<LibraryPtr> & MinecraftProfile::getVanillaLibraries() const
+{
+	return vanillaLibraries;
 }
 
 void MinecraftProfile::installJarMods(QStringList selectedFiles)
diff --git a/logic/minecraft/MinecraftProfile.h b/logic/minecraft/MinecraftProfile.h
index 84d3ce3b..24d13609 100644
--- a/logic/minecraft/MinecraftProfile.h
+++ b/logic/minecraft/MinecraftProfile.h
@@ -88,16 +88,40 @@ public:
 	/// apply the patches. Catches all the errors and returns true/false for success/failure
 	bool reapplySafe();
 
-	/// do a finalization step (should always be done after applying all patches to profile)
-	void finalize();
+public:
+	void applyMinecraftVersion(const QString& id);
+	void applyMainClass(const QString& mainClass);
+	void applyAppletClass(const QString& appletClass);
+	void applyMinecraftArguments(const QString& minecraftArguments, bool isMinecraft);
+	void applyMinecraftVersionType(const QString& type);
+	void applyMinecraftAssets(const QString& assets);
+	void applyTraits(const QSet<QString> &traits);
+	void applyTweakers(const QStringList &tweakers);
+	void applyJarMods(const QList<JarmodPtr>&jarMods);
+	void applyLibrary(LibraryPtr library, bool isMinecraft);
 
 public:
 	/// get all java libraries that belong to the classpath
-	QList<LibraryPtr> getActiveNormalLibs();
+	QList<LibraryPtr> getActiveNormalLibs() const;
 
 	/// get all native libraries that need to be available to the process
-	QList<LibraryPtr> getActiveNativeLibs();
+	QList<LibraryPtr> getActiveNativeLibs() const;
 
+	QString getMinecraftVersion() const;
+	QString getMainClass() const;
+	QString getAppletClass() const;
+	QString getMinecraftVersionType() const;
+	QString getMinecraftAssets() const;
+	QString getMinecraftArguments() const;
+	QString getVanillaMinecraftArguments() const;
+	const QSet<QString> & getTraits() const;
+	const QStringList & getTweakers() const;
+	const QList<JarmodPtr> & getJarMods() const;
+	const QList<LibraryPtr> & getLibraries() const;
+	const QList<LibraryPtr> & getVanillaLibraries() const;
+	bool hasTrait(const QString & trait) const;
+
+public:
 	/// get file ID of the patch file at #
 	QString versionFileId(const int index) const;
 
@@ -110,34 +134,22 @@ public:
 	/// save the current patch order
 	void saveCurrentOrder() const;
 
-public: /* only use in ProfileStrategy */
 	/// Remove all the patches
 	void clearPatches();
 
 	/// Add the patch object to the internal list of patches
 	void appendPatch(ProfilePatchPtr patch);
 
-public: /* data */
+protected: /* data */
 	/// the ID - determines which jar to use! ACTUALLY IMPORTANT!
 	QString id;
 
-	/// the time this version was actually released by Mojang
-	QDateTime m_releaseTime;
-
-	/// the time this version was last updated by Mojang
-	QDateTime m_updateTime;
-
 	/// Release type - "release" or "snapshot"
 	QString type;
+
 	/// Assets type - "legacy" or a version ID
 	QString assets;
-	/**
-	 * DEPRECATED: Old versions of the new vanilla launcher used this
-	 * ex: "username_session_version"
-	 */
-	QString processArguments;
-	/// Same as above, but only for vanilla
-	QString vanillaProcessArguments;
+
 	/**
 	 * arguments that should be used for launching minecraft
 	 *
@@ -145,19 +157,17 @@ public: /* data */
 	 *      --version ${version_name} --gameDir ${game_directory} --assetsDir ${game_assets}"
 	 */
 	QString minecraftArguments;
+
 	/// Same as above, but only for vanilla
 	QString vanillaMinecraftArguments;
-	/**
-	 * A list of all tweaker classes
-	 */
+
+	/// A list of all tweaker classes
 	QStringList tweakers;
-	/**
-	 * The main class to load first
-	 */
+
+	/// The main class to load first
 	QString mainClass;
-	/**
-	 * The applet class, for some very old minecraft releases
-	 */
+
+	/// The applet class, for some very old minecraft releases
 	QString appletClass;
 
 	/// the list of libs - both active and inactive, native and java
diff --git a/logic/minecraft/MinecraftVersion.cpp b/logic/minecraft/MinecraftVersion.cpp
index 8a1ac501..3224de4c 100644
--- a/logic/minecraft/MinecraftVersion.cpp
+++ b/logic/minecraft/MinecraftVersion.cpp
@@ -43,6 +43,11 @@ QString MinecraftVersion::typeString() const
 	}
 }
 
+VersionSource MinecraftVersion::getVersionSource()
+{
+	return m_versionSource;
+}
+
 bool MinecraftVersion::hasJarMods()
 {
 	return false;
@@ -64,19 +69,6 @@ void MinecraftVersion::applyFileTo(MinecraftProfile *version)
 		throw VersionIncomplete(QObject::tr("Can't apply incomplete/builtin Minecraft version %1").arg(m_name));
 	}
 }
-/*
-QJsonDocument MinecraftVersion::toJson(bool saveOrder)
-{
-	if(m_versionSource == Local && getVersionFile())
-	{
-		return getVersionFile()->toJson(saveOrder);
-	}
-	else
-	{
-		throw VersionIncomplete(QObject::tr("Can't write incomplete/builtin Minecraft version %1").arg(m_name));
-	}
-}
-*/
 
 QString MinecraftVersion::getUrl() const
 {
@@ -171,36 +163,12 @@ void MinecraftVersion::applyTo(MinecraftProfile *version)
 		throw VersionIncomplete(QObject::tr(
 			"Minecraft version %1 could not be applied: version files are missing.").arg(m_descriptor));
 	}
-	if (!m_descriptor.isNull())
-	{
-		version->id = m_descriptor;
-	}
-	if (!m_mainClass.isNull())
-	{
-		version->mainClass = m_mainClass;
-	}
-	if (!m_appletClass.isNull())
-	{
-		version->appletClass = m_appletClass;
-	}
-	if (!m_processArguments.isNull())
-	{
-		version->vanillaProcessArguments = m_processArguments;
-		version->processArguments = m_processArguments;
-	}
-	if (!m_type.isNull())
-	{
-		version->type = m_type;
-	}
-	if (!m_releaseTime.isNull())
-	{
-		version->m_releaseTime = m_releaseTime;
-	}
-	if (!m_updateTime.isNull())
-	{
-		version->m_updateTime = m_updateTime;
-	}
-	version->traits.unite(m_traits);
+	version->applyMinecraftVersion(m_descriptor);
+	version->applyMainClass(m_mainClass);
+	version->applyAppletClass(m_appletClass);
+	version->applyMinecraftArguments(" ${auth_player_name} ${auth_session}", true); // all builtin versions are legacy
+	version->applyMinecraftVersionType(m_type);
+	version->applyTraits(m_traits);
 }
 
 int MinecraftVersion::getOrder()
@@ -218,22 +186,27 @@ QList<JarmodPtr> MinecraftVersion::getJarMods()
 	return QList<JarmodPtr>();
 }
 
-QString MinecraftVersion::getPatchName()
+QString MinecraftVersion::getName()
 {
 	return "Minecraft";
 }
-QString MinecraftVersion::getPatchVersion()
+QString MinecraftVersion::getVersion()
 {
 	return m_descriptor;
 }
-QString MinecraftVersion::getPatchID()
+QString MinecraftVersion::getID()
 {
 	return "net.minecraft";
 }
-QString MinecraftVersion::getPatchFilename()
+QString MinecraftVersion::getFilename()
 {
 	return QString();
 }
+QDateTime MinecraftVersion::getReleaseDateTime()
+{
+	return m_releaseTime;
+}
+
 
 bool MinecraftVersion::needsUpdate()
 {
diff --git a/logic/minecraft/MinecraftVersion.h b/logic/minecraft/MinecraftVersion.h
index 33ca2899..aca9c08d 100644
--- a/logic/minecraft/MinecraftVersion.h
+++ b/logic/minecraft/MinecraftVersion.h
@@ -22,7 +22,6 @@
 #include "BaseVersion.h"
 #include "ProfilePatch.h"
 #include "VersionFile.h"
-#include "VersionSource.h"
 
 #include "multimc_logic_export.h"
 
@@ -32,6 +31,8 @@ typedef std::shared_ptr<MinecraftVersion> MinecraftVersionPtr;
 
 class MULTIMC_LOGIC_EXPORT MinecraftVersion : public BaseVersion, public ProfilePatch
 {
+friend class MinecraftVersionList;
+
 public: /* methods */
 	bool usesLegacyLauncher();
 	virtual QString descriptor() override;
@@ -43,10 +44,13 @@ public: /* methods */
 	virtual int getOrder() override;
 	virtual void setOrder(int order) override;
 	virtual QList<JarmodPtr> getJarMods() override;
-	virtual QString getPatchID() override;
-	virtual QString getPatchVersion() override;
-	virtual QString getPatchName() override;
-	virtual QString getPatchFilename() override;
+	virtual QString getID() override;
+	virtual QString getVersion() override;
+	virtual QString getName() override;
+	virtual QString getFilename() override;
+	QDateTime getReleaseDateTime() override;
+	VersionSource getVersionSource() override;
+
 	bool needsUpdate();
 	bool hasUpdate();
 	virtual bool isCustom() override;
@@ -84,7 +88,7 @@ public: /* methods */
 private: /* methods */
 	void applyFileTo(MinecraftProfile *version);
 
-public: /* data */
+protected: /* data */
 	VersionSource m_versionSource = Builtin;
 
 	/// The URL that this version will be downloaded from.
@@ -105,9 +109,6 @@ public: /* data */
 	/// The applet class this version uses (if any, can be empty).
 	QString m_appletClass;
 
-	/// The process arguments used by this version
-	QString m_processArguments;
-
 	/// The type of this release
 	QString m_type;
 
@@ -126,7 +127,6 @@ public: /* data */
 	/// an update available from Mojang
 	MinecraftVersionPtr upstreamUpdate;
 
-private: /* data */
 	QDateTime m_loadedVersionFileTimestamp;
 	mutable VersionFilePtr m_loadedVersionFile;
 };
diff --git a/logic/minecraft/MinecraftVersionList.cpp b/logic/minecraft/MinecraftVersionList.cpp
index 507d8254..f219c782 100644
--- a/logic/minecraft/MinecraftVersionList.cpp
+++ b/logic/minecraft/MinecraftVersionList.cpp
@@ -111,7 +111,7 @@ static bool cmpVersions(BaseVersionPtr first, BaseVersionPtr second)
 {
 	auto left = std::dynamic_pointer_cast<MinecraftVersion>(first);
 	auto right = std::dynamic_pointer_cast<MinecraftVersion>(second);
-	return left->m_releaseTime > right->m_releaseTime;
+	return left->getReleaseDateTime() > right->getReleaseDateTime();
 }
 
 void MinecraftVersionList::sortInternal()
@@ -191,7 +191,6 @@ void MinecraftVersionList::loadBuiltinList()
 		mcVersion->m_appletClass = versionObj.value("appletClass").toString("");
 		mcVersion->m_mainClass = versionObj.value("mainClass").toString("");
 		mcVersion->m_jarChecksum = versionObj.value("checksum").toString("");
-		mcVersion->m_processArguments = versionObj.value("processArguments").toString("legacy");
 		if (versionObj.contains("+traits"))
 		{
 			for (auto traitVal : Json::requireArray(versionObj.value("+traits")))
diff --git a/logic/minecraft/MojangVersionFormat.cpp b/logic/minecraft/MojangVersionFormat.cpp
index def388bf..2d4f26c5 100644
--- a/logic/minecraft/MojangVersionFormat.cpp
+++ b/logic/minecraft/MojangVersionFormat.cpp
@@ -150,7 +150,7 @@ VersionFilePtr MojangVersionFormat::versionFileFromJson(const QJsonDocument &doc
 	Bits::readString(root, "id", out->id);
 
 	Bits::readString(root, "mainClass", out->mainClass);
-	Bits::readString(root, "minecraftArguments", out->overwriteMinecraftArguments);
+	Bits::readString(root, "minecraftArguments", out->minecraftArguments);
 	Bits::readString(root, "type", out->type);
 
 	if(root.contains("assetIndex"))
@@ -203,8 +203,7 @@ QJsonDocument versionFileToJson(VersionFilePtr patch)
 	QJsonObject root;
 	writeString(root, "id", patch->id);
 	writeString(root, "mainClass", patch->mainClass);
-	writeString(root, "processArguments", patch->processArguments);
-	writeString(root, "minecraftArguments", patch->overwriteMinecraftArguments);
+	writeString(root, "minecraftArguments", patch->minecraftArguments);
 	writeString(root, "type", patch->type);
 	writeString(root, "assets", patch->assets);
 	writeString(root, "releaseTime", timeToS3Time(patch->m_releaseTime));
@@ -246,7 +245,7 @@ QJsonDocument versionFileToJson(VersionFilePtr patch)
 
 static QJsonDocument minecraftVersionToJson(MinecraftVersionPtr patch)
 {
-	if(patch->m_versionSource == Local && patch->getVersionFile())
+	if(patch->getVersionSource() == Local && patch->getVersionFile())
 	{
 		return MojangVersionFormat::profilePatchToJson(patch->getVersionFile());
 	}
@@ -268,7 +267,7 @@ QJsonDocument MojangVersionFormat::profilePatchToJson(const ProfilePatchPtr &pat
 	{
 		return minecraftVersionToJson(mversion);
 	}
-	throw VersionIncomplete(QObject::tr("Unhandled object type while processing %1").arg(patch->getPatchName()));
+	throw VersionIncomplete(QObject::tr("Unhandled object type while processing %1").arg(patch->getName()));
 }
 
 LibraryPtr MojangVersionFormat::libraryFromJson(const QJsonObject &libObj, const QString &filename)
diff --git a/logic/minecraft/ProfilePatch.h b/logic/minecraft/ProfilePatch.h
index cf7a1904..0d01ba87 100644
--- a/logic/minecraft/ProfilePatch.h
+++ b/logic/minecraft/ProfilePatch.h
@@ -14,6 +14,14 @@ enum ProblemSeverity
 	PROBLEM_ERROR
 };
 
+/// where is a version from?
+enum VersionSource
+{
+	Builtin, //!< version loaded from the internal resources.
+	Local, //!< version loaded from a file in the cache.
+	Remote, //!< incomplete version on a remote server.
+};
+
 class PatchProblem
 {
 public:
@@ -56,10 +64,14 @@ public:
 	virtual void setOrder(int order) = 0;
 	virtual int getOrder() = 0;
 
-	virtual QString getPatchID() = 0;
-	virtual QString getPatchName() = 0;
-	virtual QString getPatchVersion() = 0;
-	virtual QString getPatchFilename() = 0;
+	virtual QString getID() = 0;
+	virtual QString getName() = 0;
+	virtual QString getVersion() = 0;
+	virtual QDateTime getReleaseDateTime() = 0;
+
+	virtual QString getFilename() = 0;
+
+	virtual VersionSource getVersionSource() = 0;
 
 	virtual const QList<PatchProblem>& getProblems()
 	{
diff --git a/logic/minecraft/ProfileUtils.cpp b/logic/minecraft/ProfileUtils.cpp
index 30e83a1f..dfff7956 100644
--- a/logic/minecraft/ProfileUtils.cpp
+++ b/logic/minecraft/ProfileUtils.cpp
@@ -166,6 +166,5 @@ void removeLwjglFromPatch(VersionFilePtr patch)
 		libs = filteredLibs;
 	};
 	filter(patch->addLibs);
-	filter(patch->overwriteLibs);
 }
 }
diff --git a/logic/minecraft/VersionFile.cpp b/logic/minecraft/VersionFile.cpp
index 410f6659..9cd8dd5e 100644
--- a/logic/minecraft/VersionFile.cpp
+++ b/logic/minecraft/VersionFile.cpp
@@ -12,22 +12,6 @@
 #include "VersionBuildError.h"
 #include <Version.h>
 
-int findLibraryByName(QList<LibraryPtr> haystack, const GradleSpecifier &needle)
-{
-	int retval = -1;
-	for (int i = 0; i < haystack.size(); ++i)
-	{
-		if (haystack.at(i)->rawName().matchName(needle))
-		{
-			// only one is allowed.
-			if (retval != -1)
-				return -1;
-			retval = i;
-		}
-	}
-	return retval;
-}
-
 bool VersionFile::isMinecraftVersion()
 {
 	return fileId == "net.minecraft";
@@ -40,105 +24,31 @@ bool VersionFile::hasJarMods()
 
 void VersionFile::applyTo(MinecraftProfile *version)
 {
-	if (!version->id.isNull() && !mcVersion.isNull())
+	auto theirVersion = version->getMinecraftVersion();
+	if (!theirVersion.isNull() && !mcVersion.isNull())
 	{
-		if (QRegExp(mcVersion, Qt::CaseInsensitive, QRegExp::Wildcard).indexIn(version->id) ==
-			-1)
+		if (QRegExp(mcVersion, Qt::CaseInsensitive, QRegExp::Wildcard).indexIn(theirVersion) == -1)
 		{
-			throw MinecraftVersionMismatch(fileId, mcVersion, version->id);
+			throw MinecraftVersionMismatch(fileId, mcVersion, theirVersion);
 		}
 	}
+	bool is_minecraft = isMinecraftVersion();
+	version->applyMinecraftVersion(id);
+	version->applyMainClass(mainClass);
+	version->applyAppletClass(appletClass);
+	version->applyMinecraftArguments(minecraftArguments, is_minecraft);
+	if (is_minecraft)
+	{
+		version->applyMinecraftVersionType(type);
+	}
+	version->applyMinecraftAssets(assets);
+	version->applyTweakers(addTweakers);
+
+	version->applyJarMods(jarMods);
+	version->applyTraits(traits);
 
-	if (!id.isNull())
-	{
-		version->id = id;
-	}
-	if (!mainClass.isNull())
-	{
-		version->mainClass = mainClass;
-	}
-	if (!appletClass.isNull())
-	{
-		version->appletClass = appletClass;
-	}
-	if (!processArguments.isNull())
-	{
-		if (isMinecraftVersion())
-		{
-			version->vanillaProcessArguments = processArguments;
-		}
-		version->processArguments = processArguments;
-	}
-	if (isMinecraftVersion())
-	{
-		if (!type.isNull())
-		{
-			version->type = type;
-		}
-		if (!m_releaseTime.isNull())
-		{
-			version->m_releaseTime = m_releaseTime;
-		}
-		if (!m_updateTime.isNull())
-		{
-			version->m_updateTime = m_updateTime;
-		}
-	}
-	if (!assets.isNull())
-	{
-		version->assets = assets;
-	}
-	if (!overwriteMinecraftArguments.isNull())
-	{
-		if (isMinecraftVersion())
-		{
-			version->vanillaMinecraftArguments = overwriteMinecraftArguments;
-		}
-		version->minecraftArguments = overwriteMinecraftArguments;
-	}
-	if (!addMinecraftArguments.isNull())
-	{
-		version->minecraftArguments += addMinecraftArguments;
-	}
-	if (shouldOverwriteTweakers)
-	{
-		version->tweakers = overwriteTweakers;
-	}
-	for (auto tweaker : addTweakers)
-	{
-		version->tweakers += tweaker;
-	}
-	version->jarMods.append(jarMods);
-	version->traits.unite(traits);
-	if (shouldOverwriteLibs)
-	{
-		QList<LibraryPtr> libs;
-		for (auto lib : overwriteLibs)
-		{
-			libs.append(Library::limitedCopy(lib));
-		}
-		if (isMinecraftVersion())
-		{
-			version->vanillaLibraries = libs;
-		}
-		version->libraries = libs;
-	}
 	for (auto addedLibrary : addLibs)
 	{
-		// find the library by name.
-		const int index = findLibraryByName(version->libraries, addedLibrary->rawName());
-		// library not found? just add it.
-		if (index < 0)
-		{
-			version->libraries.append(Library::limitedCopy(addedLibrary));
-			continue;
-		}
-		auto existingLibrary = version->libraries.at(index);
-		// if we are higher it means we should update
-		if (Version(addedLibrary->version()) > Version(existingLibrary->version()))
-		{
-			auto library = Library::limitedCopy(addedLibrary);
-			version->libraries.replace(index, library);
-		}
+		version->applyLibrary(addedLibrary, isMinecraftVersion());
 	}
 }
diff --git a/logic/minecraft/VersionFile.h b/logic/minecraft/VersionFile.h
index 6c0225b0..69866fc5 100644
--- a/logic/minecraft/VersionFile.h
+++ b/logic/minecraft/VersionFile.h
@@ -20,6 +20,8 @@ struct MojangAssetIndexInfo;
 typedef std::shared_ptr<VersionFile> VersionFilePtr;
 class VersionFile : public ProfilePatch
 {
+	friend class MojangVersionFormat;
+	friend class OneSixVersionFormat;
 public: /* methods */
 	virtual void applyTo(MinecraftProfile *version) override;
 	virtual bool isMinecraftVersion() override;
@@ -36,22 +38,32 @@ public: /* methods */
 	{
 		return jarMods;
 	}
-	virtual QString getPatchID() override
+	virtual QString getID() override
 	{
 		return fileId;
 	}
-	virtual QString getPatchName() override
+	virtual QString getName() override
 	{
 		return name;
 	}
-	virtual QString getPatchVersion() override
+	virtual QString getVersion() override
 	{
 		return version;
 	}
-	virtual QString getPatchFilename() override
+	virtual QString getFilename() override
 	{
 		return filename;
 	}
+	virtual QDateTime getReleaseDateTime() override
+	{
+		return m_releaseTime;
+	}
+	VersionSource getVersionSource() override
+	{
+		return Local;
+	}
+
+
 	virtual bool isCustom() override
 	{
 		return !m_isVanilla;
@@ -138,17 +150,11 @@ public: /* data */
 	/// Mojang: class to launch Minecraft with
 	QString mainClass;
 
-	/// MultiMC: class to launch legacy Minecraft with (ambed in a custom window)
+	/// MultiMC: DEPRECATED class to launch legacy Minecraft with (ambed in a custom window)
 	QString appletClass;
 
 	/// Mojang: Minecraft launch arguments (may contain placeholders for variable substitution)
-	QString overwriteMinecraftArguments;
-
-	/// MultiMC: Minecraft launch arguments, additive variant
-	QString addMinecraftArguments;
-
-	/// Mojang: DEPRECATED variant of the Minecraft arguments, hardcoded, do not use!
-	QString processArguments;
+	QString minecraftArguments;
 
 	/// Mojang: type of the Minecraft version
 	QString type;
@@ -162,17 +168,9 @@ public: /* data */
 	/// Mojang: DEPRECATED asset group to be used with Minecraft
 	QString assets;
 
-	/// MultiMC: override list of tweaker mod arguments for launchwrapper (replaces the previously assembled lists)
-	bool shouldOverwriteTweakers = false;
-	QStringList overwriteTweakers;
-
 	/// MultiMC: list of tweaker mod arguments for launchwrapper
 	QStringList addTweakers;
 
-	/// MultiMC: override list of libraries (replaces the previously assembled lists)
-	bool shouldOverwriteLibs = false;
-	QList<LibraryPtr> overwriteLibs;
-
 	/// Mojang: list of libraries to add to the version
 	QList<LibraryPtr> addLibs;
 
@@ -182,6 +180,7 @@ public: /* data */
 	/// MultiMC: list of jar mods added to this version
 	QList<JarmodPtr> jarMods;
 
+public:
 	// Mojang: list of 'downloads' - client jar, server jar, windows server exe, maybe more.
 	QMap <QString, std::shared_ptr<MojangDownloadInfo>> mojangDownloads;
 
diff --git a/logic/minecraft/VersionSource.h b/logic/minecraft/VersionSource.h
deleted file mode 100644
index 75b2c24b..00000000
--- a/logic/minecraft/VersionSource.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#pragma once
-
-/// where is a version from?
-enum VersionSource
-{
-	Builtin, //!< version loaded from the internal resources.
-	Local, //!< version loaded from a file in the cache.
-	Remote, //!< incomplete version on a remote server.
-};
\ No newline at end of file
diff --git a/logic/minecraft/forge/ForgeInstaller.cpp b/logic/minecraft/forge/ForgeInstaller.cpp
index bc0a967e..a72160a2 100644
--- a/logic/minecraft/forge/ForgeInstaller.cpp
+++ b/logic/minecraft/forge/ForgeInstaller.cpp
@@ -119,7 +119,7 @@ void ForgeInstaller::prepare(const QString &filename, const QString &universalUr
 	file.close();
 
 	m_forge_json = newVersion;
-	m_forge_json->id = installObj.value("minecraft").toString();
+	//m_forge_json->id = installObj.value("minecraft").toString();
 }
 
 bool ForgeInstaller::add(OneSixInstance *to)
@@ -134,15 +134,14 @@ bool ForgeInstaller::add(OneSixInstance *to)
 
 	if (!m_forge_json)
 		return false;
-	int sliding_insert_window = 0;
 	{
-		QJsonArray librariesPlus;
+		QJsonArray libraries;
 		// A blacklist
 		QSet<QString> blacklist{"authlib", "realms"};
 		//
 		QList<QString> xzlist{"org.scala-lang", "com.typesafe"};
 		// for each library in the version we are adding (except for the blacklisted)
-		for (auto lib : m_forge_json->libraries)
+		for (auto lib : m_forge_json->getLibraries())
 		{
 			QString libName = lib->artifactId();
 			QString rawName = lib->rawName();
@@ -194,41 +193,27 @@ bool ForgeInstaller::add(OneSixInstance *to)
 
 			QJsonObject libObj = OneSixVersionFormat::libraryToJson(lib.get());
 
-			bool found = false;
 			bool equals = false;
 			// find an entry that matches this one
-			for (auto tolib : to->getMinecraftProfile()->vanillaLibraries)
+			for (auto tolib : to->getMinecraftProfile()->getVanillaLibraries())
 			{
 				if (tolib->artifactId() != libName)
 					continue;
-				found = true;
 				if (OneSixVersionFormat::libraryToJson(tolib.get()) == libObj)
 				{
 					equals = true;
 				}
-				// replace lib
-				libObj.insert("insert", QString("replace"));
 				break;
 			}
 			if (equals)
 			{
 				continue;
 			}
-			if (!found)
-			{
-				// add lib
-				libObj.insert("insert", QString("prepend"));
-				if (lib->artifactId() == "minecraftforge" || lib->artifactId() == "forge")
-				{
-					libObj.insert("MMC-depend", QString("hard"));
-				}
-				sliding_insert_window++;
-			}
-			librariesPlus.prepend(libObj);
+			libraries.append(libObj);
 		}
-		obj.insert("+libraries", librariesPlus);
-		obj.insert("mainClass", m_forge_json->mainClass);
-		QString args = m_forge_json->minecraftArguments;
+		obj.insert("libraries", libraries);
+		obj.insert("mainClass", m_forge_json->getMainClass());
+		QString args = m_forge_json->getMinecraftArguments();
 		QStringList tweakers;
 		{
 			QRegularExpression expression("--tweakClass ([a-zA-Z0-9\\.]*)");
@@ -240,7 +225,7 @@ bool ForgeInstaller::add(OneSixInstance *to)
 				match = expression.match(args);
 			}
 		}
-		if (!args.isEmpty() && args != to->getMinecraftProfile()->vanillaMinecraftArguments)
+		if (!args.isEmpty() && args != to->getMinecraftProfile()->getVanillaMinecraftArguments())
 		{
 			obj.insert("minecraftArguments", args);
 		}
@@ -248,11 +233,6 @@ bool ForgeInstaller::add(OneSixInstance *to)
 		{
 			obj.insert("+tweakers", QJsonArray::fromStringList(tweakers));
 		}
-		if (!m_forge_json->processArguments.isEmpty() &&
-			m_forge_json->processArguments != to->getMinecraftProfile()->vanillaProcessArguments)
-		{
-			obj.insert("processArguments", m_forge_json->processArguments);
-		}
 	}
 
 	obj.insert("name", QString("Forge"));
diff --git a/logic/minecraft/ftb/FTBProfileStrategy.cpp b/logic/minecraft/ftb/FTBProfileStrategy.cpp
index a86cdee3..6f635fe8 100644
--- a/logic/minecraft/ftb/FTBProfileStrategy.cpp
+++ b/logic/minecraft/ftb/FTBProfileStrategy.cpp
@@ -54,9 +54,6 @@ void FTBProfileStrategy::loadDefaultBuiltinPatches()
 			auto file = ProfileUtils::parseJsonFile(QFileInfo(mcJson), false);
 
 			// adapt the loaded file - the FTB patch file format is different than ours.
-			file->addLibs = file->overwriteLibs;
-			file->overwriteLibs.clear();
-			file->shouldOverwriteLibs = false;
 			file->id.clear();
 			for(auto addLib: file->addLibs)
 			{
@@ -98,8 +95,6 @@ void FTBProfileStrategy::load()
 
 	loadDefaultBuiltinPatches();
 	loadUserPatches();
-
-	profile->finalize();
 }
 
 bool FTBProfileStrategy::saveOrder(ProfileUtils::PatchOrder order)
diff --git a/logic/minecraft/onesix/OneSixInstance.cpp b/logic/minecraft/onesix/OneSixInstance.cpp
index 2846640c..93034925 100644
--- a/logic/minecraft/onesix/OneSixInstance.cpp
+++ b/logic/minecraft/onesix/OneSixInstance.cpp
@@ -61,7 +61,7 @@ QSet<QString> OneSixInstance::traits()
 		return {"version-incomplete"};
 	}
 	else
-		return version->traits;
+		return version->getTraits();
 }
 
 std::shared_ptr<Task> OneSixInstance::createUpdateTask()
@@ -95,8 +95,8 @@ QString replaceTokensIn(QString text, QMap<QString, QString> with)
 
 QStringList OneSixInstance::processMinecraftArgs(AuthSessionPtr session)
 {
-	QString args_pattern = m_version->minecraftArguments;
-	for (auto tweaker : m_version->tweakers)
+	QString args_pattern = m_version->getMinecraftArguments();
+	for (auto tweaker : m_version->getTweakers())
 	{
 		args_pattern += " --tweakClass " + tweaker;
 	}
@@ -113,7 +113,7 @@ QStringList OneSixInstance::processMinecraftArgs(AuthSessionPtr session)
 	token_mapping["profile_name"] = token_mapping["version_name"] = "MultiMC5";
 	if(m_version->isVanilla())
 	{
-		token_mapping["version_type"] = m_version->type;
+		token_mapping["version_type"] = m_version->getMinecraftVersionType();
 	}
 	else
 	{
@@ -123,24 +123,14 @@ QStringList OneSixInstance::processMinecraftArgs(AuthSessionPtr session)
 	QString absRootDir = QDir(minecraftRoot()).absolutePath();
 	token_mapping["game_directory"] = absRootDir;
 	QString absAssetsDir = QDir("assets/").absolutePath();
-	token_mapping["game_assets"] = AssetsUtils::reconstructAssets(m_version->assets).absolutePath();
+	token_mapping["game_assets"] = AssetsUtils::reconstructAssets(m_version->getMinecraftAssets()).absolutePath();
 
 	token_mapping["user_properties"] = session->serializeUserProperties();
 	token_mapping["user_type"] = session->user_type;
 
 	// 1.7.3+ assets tokens
 	token_mapping["assets_root"] = absAssetsDir;
-	token_mapping["assets_index_name"] = m_version->assets;
-
-	// 1.9+ version type token
-	if(m_version->isVanilla())
-	{
-		token_mapping["version_type"] = m_version->type;
-	}
-	else
-	{
-		token_mapping["version_type"] = "custom";
-	}
+	token_mapping["assets_index_name"] = m_version->getMinecraftAssets();
 
 	QStringList parts = args_pattern.split(' ', QString::SkipEmptyParts);
 	for (int i = 0; i < parts.length(); i++)
@@ -182,7 +172,7 @@ QString OneSixInstance::createLaunchScript(AuthSessionPtr session)
 		launchScript += "coremod " + coremod.filename().completeBaseName()  + "\n";;
 	}
 
-	for(auto & jarmod: m_version->jarMods)
+	for(auto & jarmod: m_version->getJarMods())
 	{
 		launchScript += "jarmod " + jarmod->originalName + " (" + jarmod->name + ")\n";
 	}
@@ -201,17 +191,19 @@ QString OneSixInstance::createLaunchScript(AuthSessionPtr session)
 		}
 		else
 		{
-			QString relpath = m_version->id + "/" + m_version->id + ".jar";
+			QString relpath = m_version->getMinecraftVersion() + "/" + m_version->getMinecraftVersion() + ".jar";
 			launchScript += "cp " + versionsPath().absoluteFilePath(relpath) + "\n";
 		}
 	}
-	if (!m_version->mainClass.isEmpty())
+	auto mainClass = m_version->getMainClass();
+	if (!mainClass.isEmpty())
 	{
-		launchScript += "mainClass " + m_version->mainClass + "\n";
+		launchScript += "mainClass " + mainClass + "\n";
 	}
-	if (!m_version->appletClass.isEmpty())
+	auto appletClass = m_version->getAppletClass();
+	if (!appletClass.isEmpty())
 	{
-		launchScript += "appletClass " + m_version->appletClass + "\n";
+		launchScript += "appletClass " + appletClass + "\n";
 	}
 
 	// generic minecraft params
@@ -251,7 +243,7 @@ QString OneSixInstance::createLaunchScript(AuthSessionPtr session)
 	}
 
 	// traits. including legacyLaunch and others ;)
-	for (auto trait : m_version->traits)
+	for (auto trait : m_version->getTraits())
 	{
 		launchScript += "traits " + trait + "\n";
 	}
@@ -323,7 +315,7 @@ std::shared_ptr<Task> OneSixInstance::createJarModdingTask()
 		{
 			std::shared_ptr<MinecraftProfile> version = m_inst->getMinecraftProfile();
 			// nuke obsolete stripped jar(s) if needed
-			QString version_id = version->id;
+			QString version_id = version->getMinecraftVersion();
 			QString strippedPath = version_id + "/" + version_id + "-stripped.jar";
 			QFile strippedJar(strippedPath);
 			if(strippedJar.exists())
@@ -351,7 +343,7 @@ std::shared_ptr<Task> OneSixInstance::createJarModdingTask()
 			auto jarMods = m_inst->getJarMods();
 			if(jarMods.size())
 			{
-				auto sourceJarPath = m_inst->versionsPath().absoluteFilePath(version->id + "/" + version->id + ".jar");
+				auto sourceJarPath = m_inst->versionsPath().absoluteFilePath(version_id + "/" + version_id + ".jar");
 				QString localPath = version_id + "/" + version_id + ".jar";
 				auto metacache = ENV.metacache();
 				auto entry = metacache->resolveEntry("versions", localPath);
@@ -439,7 +431,7 @@ bool OneSixInstance::setIntendedVersionId(QString version)
 QList< Mod > OneSixInstance::getJarMods() const
 {
 	QList<Mod> mods;
-	for (auto jarmod : m_version->jarMods)
+	for (auto jarmod : m_version->getJarMods())
 	{
 		QString filePath = jarmodsPath().absoluteFilePath(jarmod->name);
 		mods.push_back(Mod(QFileInfo(filePath)));
diff --git a/logic/minecraft/onesix/OneSixProfileStrategy.cpp b/logic/minecraft/onesix/OneSixProfileStrategy.cpp
index fe4e0d26..baec635e 100644
--- a/logic/minecraft/onesix/OneSixProfileStrategy.cpp
+++ b/logic/minecraft/onesix/OneSixProfileStrategy.cpp
@@ -228,8 +228,6 @@ void OneSixProfileStrategy::load()
 	upgradeDeprecatedFiles();
 	loadDefaultBuiltinPatches();
 	loadUserPatches();
-
-	profile->finalize();
 }
 
 bool OneSixProfileStrategy::saveOrder(ProfileUtils::PatchOrder order)
@@ -246,7 +244,7 @@ bool OneSixProfileStrategy::removePatch(ProfilePatchPtr patch)
 {
 	bool ok = true;
 	// first, remove the patch file. this ensures it's not used anymore
-	auto fileName = patch->getPatchFilename();
+	auto fileName = patch->getFilename();
 	if(fileName.size())
 	{
 		QFile patchFile(fileName);
@@ -289,7 +287,7 @@ bool OneSixProfileStrategy::customizePatch(ProfilePatchPtr patch)
 		return false;
 	}
 
-	auto filename = FS::PathCombine(m_instance->instanceRoot(), "patches" , patch->getPatchID() + ".json");
+	auto filename = FS::PathCombine(m_instance->instanceRoot(), "patches" , patch->getID() + ".json");
 	if(!FS::ensureFilePathExists(filename))
 	{
 		return false;
@@ -327,7 +325,7 @@ bool OneSixProfileStrategy::revertPatch(ProfilePatchPtr patch)
 		// already not custom
 		return true;
 	}
-	auto filename = patch->getPatchFilename();
+	auto filename = patch->getFilename();
 	if(!QFile::exists(filename))
 	{
 		// already gone / not custom
diff --git a/logic/minecraft/onesix/OneSixUpdate.cpp b/logic/minecraft/onesix/OneSixUpdate.cpp
index da3bd504..c12674d4 100644
--- a/logic/minecraft/onesix/OneSixUpdate.cpp
+++ b/logic/minecraft/onesix/OneSixUpdate.cpp
@@ -51,8 +51,7 @@ void OneSixUpdate::executeTask()
 	}
 
 	// Get a pointer to the version object that corresponds to the instance's version.
-	targetVersion = std::dynamic_pointer_cast<MinecraftVersion>(
-		ENV.getVersion("net.minecraft", m_inst->intendedVersionId()));
+	targetVersion = std::dynamic_pointer_cast<MinecraftVersion>(ENV.getVersion("net.minecraft", m_inst->intendedVersionId()));
 	if (targetVersion == nullptr)
 	{
 		// don't do anything if it was invalid
@@ -89,7 +88,7 @@ void OneSixUpdate::assetIndexStart()
 	setStatus(tr("Updating assets index..."));
 	OneSixInstance *inst = (OneSixInstance *)m_inst;
 	std::shared_ptr<MinecraftProfile> version = inst->getMinecraftProfile();
-	QString assetName = version->assets;
+	QString assetName = version->getMinecraftAssets();
 	QUrl indexUrl = "http://" + URLConstants::AWS_DOWNLOAD_INDEXES + assetName + ".json";
 	QString localPath = assetName + ".json";
 	auto job = new NetJob(tr("Asset index for %1").arg(inst->name()));
@@ -115,7 +114,7 @@ void OneSixUpdate::assetIndexFinished()
 
 	OneSixInstance *inst = (OneSixInstance *)m_inst;
 	std::shared_ptr<MinecraftProfile> version = inst->getMinecraftProfile();
-	QString assetName = version->assets;
+	QString assetName = version->getMinecraftAssets();
 
 	QString asset_fname = "assets/indexes/" + assetName + ".json";
 	if (!AssetsUtils::loadAssetsIndexJson(asset_fname, &index))
@@ -194,7 +193,7 @@ void OneSixUpdate::jarlibStart()
 	std::shared_ptr<MinecraftProfile> version = inst->getMinecraftProfile();
 	// minecraft.jar for this version
 	{
-		QString version_id = version->id;
+		QString version_id = version->getMinecraftVersion();
 		QString localPath = version_id + "/" + version_id + ".jar";
 		QString urlstr = "http://" + URLConstants::AWS_DOWNLOAD_VERSIONS + localPath;
 
@@ -292,7 +291,7 @@ void OneSixUpdate::jarlibFinished()
 	OneSixInstance *inst = (OneSixInstance *)m_inst;
 	std::shared_ptr<MinecraftProfile> version = inst->getMinecraftProfile();
 
-	if (version->traits.contains("legacyFML"))
+	if (version->hasTrait("legacyFML"))
 	{
 		fmllibsStart();
 	}
diff --git a/logic/minecraft/onesix/OneSixVersionFormat.cpp b/logic/minecraft/onesix/OneSixVersionFormat.cpp
index 4ccf6e78..ff26ab92 100644
--- a/logic/minecraft/onesix/OneSixVersionFormat.cpp
+++ b/logic/minecraft/onesix/OneSixVersionFormat.cpp
@@ -81,9 +81,30 @@ VersionFilePtr OneSixVersionFormat::versionFileFromJson(const QJsonDocument &doc
 
 	readString(root, "mainClass", out->mainClass);
 	readString(root, "appletClass", out->appletClass);
-	readString(root, "processArguments", out->processArguments);
-	readString(root, "minecraftArguments", out->overwriteMinecraftArguments);
-	readString(root, "+minecraftArguments", out->addMinecraftArguments);
+	readString(root, "minecraftArguments", out->minecraftArguments);
+	if(out->minecraftArguments.isEmpty())
+	{
+		QString processArguments;
+		readString(root, "processArguments", processArguments);
+		QString toCompare = processArguments.toLower();
+		if (toCompare == "legacy")
+		{
+			out->minecraftArguments = " ${auth_player_name} ${auth_session}";
+		}
+		else if (toCompare == "username_session")
+		{
+			out->minecraftArguments = "--username ${auth_player_name} --session ${auth_session}";
+		}
+		else if (toCompare == "username_session_version")
+		{
+			out->minecraftArguments = "--username ${auth_player_name} --session ${auth_session} --version ${profile_name}";
+		}
+		else if (!toCompare.isEmpty())
+		{
+			out->addProblem(PROBLEM_ERROR, QObject::tr("processArguments is set to unknown value '%1'").arg(processArguments));
+		}
+	}
+
 	readString(root, "type", out->type);
 
 	out->m_releaseTime = timeFromS3Time(readStringRet(root, "releaseTime"));
@@ -91,15 +112,6 @@ VersionFilePtr OneSixVersionFormat::versionFileFromJson(const QJsonDocument &doc
 
 	readString(root, "assets", out->assets);
 
-	if (root.contains("tweakers"))
-	{
-		out->shouldOverwriteTweakers = true;
-		for (auto tweakerVal : requireArray(root.value("tweakers")))
-		{
-			out->overwriteTweakers.append(requireString(tweakerVal));
-		}
-	}
-
 	if (root.contains("+tweakers"))
 	{
 		for (auto tweakerVal : requireArray(root.value("+tweakers")))
@@ -108,7 +120,6 @@ VersionFilePtr OneSixVersionFormat::versionFileFromJson(const QJsonDocument &doc
 		}
 	}
 
-
 	if (root.contains("+traits"))
 	{
 		for (auto tweakerVal : requireArray(root.value("+traits")))
@@ -117,18 +128,6 @@ VersionFilePtr OneSixVersionFormat::versionFileFromJson(const QJsonDocument &doc
 		}
 	}
 
-	if (root.contains("libraries"))
-	{
-		out->shouldOverwriteLibs = true;
-		for (auto libVal : requireArray(root.value("libraries")))
-		{
-			auto libObj = requireObject(libVal);
-
-			auto lib = libraryFromJson(libObj, filename);
-			out->overwriteLibs.append(lib);
-		}
-	}
-
 	if (root.contains("+jarMods"))
 	{
 		for (auto libVal : requireArray(root.value("+jarMods")))
@@ -147,18 +146,38 @@ VersionFilePtr OneSixVersionFormat::versionFileFromJson(const QJsonDocument &doc
 		}
 	}
 
-	if (root.contains("+libraries"))
+	auto readLibs = [&](const char * which)
 	{
-		for (auto libVal : requireArray(root.value("+libraries")))
+		for (auto libVal : requireArray(root.value(which)))
 		{
 			QJsonObject libObj = requireObject(libVal);
 			// parse the library
 			auto lib = libraryFromJson(libObj, filename);
 			out->addLibs.append(lib);
 		}
+	};
+	bool hasPlusLibs = root.contains("+libraries");
+	bool hasLibs = root.contains("libraries");
+	if (hasPlusLibs && hasLibs)
+	{
+		out->addProblem(PROBLEM_WARNING, QObject::tr("Version file has both '+libraries' and 'libraries'. This is no longer supported."));
+		readLibs("libraries");
+		readLibs("+libraries");
+	}
+	else if (hasLibs)
+	{
+		readLibs("libraries");
+	}
+	else if(hasPlusLibs)
+	{
+		readLibs("+libraries");
 	}
 
 	/* removed features that shouldn't be used */
+	if (root.contains("tweakers"))
+	{
+		out->addProblem(PROBLEM_ERROR, QObject::tr("Version file contains unsupported element 'tweakers'"));
+	}
 	if (root.contains("-libraries"))
 	{
 		out->addProblem(PROBLEM_ERROR, QObject::tr("Version file contains unsupported element '-libraries'"));
@@ -171,6 +190,10 @@ VersionFilePtr OneSixVersionFormat::versionFileFromJson(const QJsonDocument &doc
 	{
 		out->addProblem(PROBLEM_ERROR, QObject::tr("Version file contains unsupported element '-minecraftArguments'"));
 	}
+	if (root.contains("+minecraftArguments"))
+	{
+		out->addProblem(PROBLEM_ERROR, QObject::tr("Version file contains unsupported element '+minecraftArguments'"));
+	}
 	return out;
 }
 
@@ -197,9 +220,7 @@ static QJsonDocument versionFileToJson(VersionFilePtr patch, bool saveOrder)
 	writeString(root, "id", patch->id);
 	writeString(root, "mainClass", patch->mainClass);
 	writeString(root, "appletClass", patch->appletClass);
-	writeString(root, "processArguments", patch->processArguments);
-	writeString(root, "minecraftArguments", patch->overwriteMinecraftArguments);
-	writeString(root, "+minecraftArguments", patch->addMinecraftArguments);
+	writeString(root, "minecraftArguments", patch->minecraftArguments);
 	writeString(root, "type", patch->type);
 	writeString(root, "assets", patch->assets);
 	if (patch->isMinecraftVersion())
@@ -207,18 +228,8 @@ static QJsonDocument versionFileToJson(VersionFilePtr patch, bool saveOrder)
 		writeString(root, "releaseTime", timeToS3Time(patch->m_releaseTime));
 		writeString(root, "time", timeToS3Time(patch->m_updateTime));
 	}
-	writeStringList(root, "tweakers", patch->overwriteTweakers);
 	writeStringList(root, "+tweakers", patch->addTweakers);
 	writeStringList(root, "+traits", patch->traits.toList());
-	if (!patch->overwriteLibs.isEmpty())
-	{
-		QJsonArray array;
-		for (auto value: patch->overwriteLibs)
-		{
-			array.append(OneSixVersionFormat::libraryToJson(value.get()));
-		}
-		root.insert("libraries", array);
-	}
 	if (!patch->addLibs.isEmpty())
 	{
 		QJsonArray array;
@@ -226,7 +237,7 @@ static QJsonDocument versionFileToJson(VersionFilePtr patch, bool saveOrder)
 		{
 			array.append(OneSixVersionFormat::libraryToJson(value.get()));
 		}
-		root.insert("+libraries", array);
+		root.insert("libraries", array);
 	}
 	if (!patch->jarMods.isEmpty())
 	{
@@ -247,7 +258,7 @@ static QJsonDocument versionFileToJson(VersionFilePtr patch, bool saveOrder)
 
 static QJsonDocument minecraftVersionToJson(MinecraftVersionPtr patch, bool saveOrder)
 {
-	if(patch->m_versionSource == Local && patch->getVersionFile())
+	if(patch->getVersionSource() == Local && patch->getVersionFile())
 	{
 		return OneSixVersionFormat::profilePatchToJson(patch->getVersionFile(), saveOrder);
 	}
@@ -269,7 +280,7 @@ QJsonDocument OneSixVersionFormat::profilePatchToJson(const ProfilePatchPtr &pat
 	{
 		return minecraftVersionToJson(mversion, saveOrder);
 	}
-	throw VersionIncomplete(QObject::tr("Unhandled object type while processing %1").arg(patch->getPatchName()));
+	throw VersionIncomplete(QObject::tr("Unhandled object type while processing %1").arg(patch->getName()));
 }
 
 std::shared_ptr<MinecraftProfile> OneSixVersionFormat::profileFromSingleJson(const QJsonObject &obj)