There are API differences between WebObjects 5.3 and WebObjects 5.4 that one may need to deal with when changing code in Project WOnder frameworks.
WO54: NSDictionary plist = NSPropertyListSerialization.dictionaryWithPathURL(url);
WO53: NSDictionary plist = (NSDictionary)NSPropertyListSerialization.propertyListWithPathURL(url);
There is a document from Apple which tells you how to identify the WebObjects version you are using. It is at: http://support.apple.com/kb/TA26706
The meat of it is that you can look in the /System/Library/Frameworks/JavaWebObjects.framework/Resources/version.plist file on your system and see something like:
<?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">
The CFBundleShortVersionString tells you that this is a WebObjects 5.4.3 installation.
You can also look at the first line of the console log of any of your applications. You will see a line like:
[2011-6-4 21:0:18 PDT] <main> WebObjects version = 5.4.3