This is a list of functional changes that I noticed when converting from WebObjects 5.3.3 to 5.4.2 / 5.4.3:

• integers in property lists (plist format anyway) are now returned as BigInteger not String
• plist property lists that formerly threw an exception due to an invalid format (e.g. just having "Foo") now return an empty collection
• calling NSPropertyListSerialization.arrayFromString() on a string that is not an array now silently returns an empty array instead of throwing an exception
• calling NSPropertyListSerialization.arrayFromString() on a string that is not a dictionary now silently returns an empty dictionary instead of throwing an exception
• The noSelectionString binding on WOPopUpButton was previously HTML escaped. Now you need to set escapeHTML=true to get this behaviour
• You used to be able to bind noSelectionString to an empty space ("") to get a blank line in a popup to indicate no selection. Now you need to bind it to at least one space (" ")
• (fixed as of 5.4.3) all of WebObjects has been converted to using UTF-8 (note the hyphen), but _NSUtilities.UTF8StringEncoding is still "UTF8". DO NOT USE THIS