diff --git a/objectivec/ProtocolBuffers_OSX.xcodeproj/project.pbxproj b/objectivec/ProtocolBuffers_OSX.xcodeproj/project.pbxproj
index f4e488b0f4..a41be9f280 100644
--- a/objectivec/ProtocolBuffers_OSX.xcodeproj/project.pbxproj
+++ b/objectivec/ProtocolBuffers_OSX.xcodeproj/project.pbxproj
@@ -637,7 +637,7 @@
 			attributes = {
 				LastSwiftUpdateCheck = 0710;
 				LastTestingUpgradeCheck = 0600;
-				LastUpgradeCheck = 0900;
+				LastUpgradeCheck = 0930;
 				TargetAttributes = {
 					8BBEA4A5147C727100C4ADB7 = {
 						LastSwiftMigration = 0800;
@@ -818,6 +818,7 @@
 		7461B52F0F94FAFA00A0C422 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				COMBINE_HIDPI_IMAGES = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)";
 				PRODUCT_NAME = ProtocolBuffers;
@@ -827,6 +828,7 @@
 		7461B5300F94FAFA00A0C422 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				COMBINE_HIDPI_IMAGES = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)";
 				PRODUCT_NAME = ProtocolBuffers;
@@ -837,6 +839,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				COMBINE_HIDPI_IMAGES = YES;
 				HEADER_SEARCH_PATHS = (
 					"${PROJECT_DERIVED_FILE_DIR}/protos",
@@ -863,6 +866,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				COMBINE_HIDPI_IMAGES = YES;
 				HEADER_SEARCH_PATHS = (
 					"${PROJECT_DERIVED_FILE_DIR}/protos",
@@ -1025,6 +1029,7 @@
 		F4487C4F1A9F8E0200531423 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				COMBINE_HIDPI_IMAGES = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)";
 				PRODUCT_NAME = TestSingleSourceBuild;
@@ -1034,6 +1039,7 @@
 		F4487C501A9F8E0200531423 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				COMBINE_HIDPI_IMAGES = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)";
 				PRODUCT_NAME = TestSingleSourceBuild;
@@ -1043,12 +1049,14 @@
 		F45BBC151B0CE3C6002D064D /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 			};
 			name = Debug;
 		};
 		F45BBC161B0CE3C6002D064D /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 			};
 			name = Release;
 		};
diff --git a/objectivec/ProtocolBuffers_OSX.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist b/objectivec/ProtocolBuffers_OSX.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
new file mode 100644
index 0000000000..18d981003d
--- /dev/null
+++ b/objectivec/ProtocolBuffers_OSX.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>
diff --git a/objectivec/ProtocolBuffers_OSX.xcodeproj/xcshareddata/xcschemes/PerformanceTests.xcscheme b/objectivec/ProtocolBuffers_OSX.xcodeproj/xcshareddata/xcschemes/PerformanceTests.xcscheme
index d3c29389ad..6653a1b02b 100644
--- a/objectivec/ProtocolBuffers_OSX.xcodeproj/xcshareddata/xcschemes/PerformanceTests.xcscheme
+++ b/objectivec/ProtocolBuffers_OSX.xcodeproj/xcshareddata/xcschemes/PerformanceTests.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0900"
+   LastUpgradeVersion = "0930"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,7 +26,6 @@
       buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -301,7 +300,6 @@
       buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/objectivec/ProtocolBuffers_OSX.xcodeproj/xcshareddata/xcschemes/ProtocolBuffers.xcscheme b/objectivec/ProtocolBuffers_OSX.xcodeproj/xcshareddata/xcschemes/ProtocolBuffers.xcscheme
index e7fb8215aa..328771b8ce 100644
--- a/objectivec/ProtocolBuffers_OSX.xcodeproj/xcshareddata/xcschemes/ProtocolBuffers.xcscheme
+++ b/objectivec/ProtocolBuffers_OSX.xcodeproj/xcshareddata/xcschemes/ProtocolBuffers.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0900"
+   LastUpgradeVersion = "0930"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -54,9 +54,8 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
-      shouldUseLaunchSchemeArgsEnv = "YES"
-      codeCoverageEnabled = "YES">
+      codeCoverageEnabled = "YES"
+      shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
             skipped = "NO">
@@ -90,7 +89,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj b/objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj
index c2683fa6a9..0c0e1810a5 100644
--- a/objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj
+++ b/objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj
@@ -714,7 +714,7 @@
 			attributes = {
 				LastSwiftUpdateCheck = 0710;
 				LastTestingUpgradeCheck = 0600;
-				LastUpgradeCheck = 0900;
+				LastUpgradeCheck = 0930;
 				TargetAttributes = {
 					8BBEA4A5147C727100C4ADB7 = {
 						LastSwiftMigration = 0800;
@@ -930,6 +930,7 @@
 		7461B52F0F94FAFA00A0C422 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)";
 				PRODUCT_NAME = ProtocolBuffers;
 				TARGETED_DEVICE_FAMILY = "1,2";
@@ -939,6 +940,7 @@
 		7461B5300F94FAFA00A0C422 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)";
 				PRODUCT_NAME = ProtocolBuffers;
 				TARGETED_DEVICE_FAMILY = "1,2";
@@ -979,6 +981,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				FRAMEWORK_SEARCH_PATHS = (
 					"\"$(DEVELOPER_LIBRARY_DIR)/Frameworks\"",
 					"$(inherited)",
@@ -1014,6 +1017,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				FRAMEWORK_SEARCH_PATHS = (
 					"\"$(DEVELOPER_LIBRARY_DIR)/Frameworks\"",
 					"$(inherited)",
@@ -1187,6 +1191,7 @@
 		F4487C6C1A9F8F8100531423 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)";
 				PRODUCT_NAME = TestSingleSourceBuild;
 				TARGETED_DEVICE_FAMILY = "1,2";
@@ -1196,6 +1201,7 @@
 		F4487C6D1A9F8F8100531423 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)";
 				PRODUCT_NAME = TestSingleSourceBuild;
 				TARGETED_DEVICE_FAMILY = "1,2";
@@ -1205,12 +1211,14 @@
 		F45BBC0F1B0CDB50002D064D /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 			};
 			name = Debug;
 		};
 		F45BBC101B0CDB50002D064D /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CLANG_ENABLE_OBJC_WEAK = YES;
 			};
 			name = Release;
 		};
diff --git a/objectivec/ProtocolBuffers_iOS.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist b/objectivec/ProtocolBuffers_iOS.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
new file mode 100644
index 0000000000..18d981003d
--- /dev/null
+++ b/objectivec/ProtocolBuffers_iOS.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>
diff --git a/objectivec/ProtocolBuffers_iOS.xcodeproj/xcshareddata/xcschemes/PerformanceTests.xcscheme b/objectivec/ProtocolBuffers_iOS.xcodeproj/xcshareddata/xcschemes/PerformanceTests.xcscheme
index 03acb0837d..77483d381c 100644
--- a/objectivec/ProtocolBuffers_iOS.xcodeproj/xcshareddata/xcschemes/PerformanceTests.xcscheme
+++ b/objectivec/ProtocolBuffers_iOS.xcodeproj/xcshareddata/xcschemes/PerformanceTests.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0900"
+   LastUpgradeVersion = "0930"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,7 +26,6 @@
       buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -310,7 +309,6 @@
       buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/objectivec/ProtocolBuffers_iOS.xcodeproj/xcshareddata/xcschemes/ProtocolBuffers.xcscheme b/objectivec/ProtocolBuffers_iOS.xcodeproj/xcshareddata/xcschemes/ProtocolBuffers.xcscheme
index 98bcd56295..69825cc5de 100644
--- a/objectivec/ProtocolBuffers_iOS.xcodeproj/xcshareddata/xcschemes/ProtocolBuffers.xcscheme
+++ b/objectivec/ProtocolBuffers_iOS.xcodeproj/xcshareddata/xcschemes/ProtocolBuffers.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0900"
+   LastUpgradeVersion = "0930"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -54,9 +54,8 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
-      shouldUseLaunchSchemeArgsEnv = "YES"
-      codeCoverageEnabled = "YES">
+      codeCoverageEnabled = "YES"
+      shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
             skipped = "NO">
@@ -90,7 +89,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"