There was a delay on 3.6 as well. Just make sure that if they delete from Outlook that they don't immediately empty their Deleted Items (permanent delete). That way, the BES/BB will be able to query between the two and know which emails need to be on the handheld and which need to be removed.
In the beginning the Universe was created. This has made a lot of people very angry and is widely regarded as a bad move.