diff --git a/build/osx/wxcocoa.xcodeproj/project.pbxproj b/build/osx/wxcocoa.xcodeproj/project.pbxproj
index 20a8f1498e..80f1ceca79 100644
--- a/build/osx/wxcocoa.xcodeproj/project.pbxproj
+++ b/build/osx/wxcocoa.xcodeproj/project.pbxproj
@@ -3,7 +3,7 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 46;
+	objectVersion = 45;
 	objects = {
 
 /* Begin PBXBuildFile section */
@@ -3976,11 +3976,8 @@
 /* Begin PBXProject section */
 		19367367C9323490BB936F06 /* Project object */ = {
 			isa = PBXProject;
-			attributes = {
-				LastUpgradeCheck = 0500;
-			};
 			buildConfigurationList = 6976B5F5F3A63A21A92029E3 /* Build configuration list for PBXProject "wxcocoa" */;
-			compatibilityVersion = "Xcode 3.2";
+			compatibilityVersion = "Xcode 3.1";
 			developmentRegion = English;
 			hasScannedForEncodings = 1;
 			knownRegions = (