The changelog for version 2.0.1 reads:
- Fixed crash when blocking user from search results
- Fixed crash with non-Roman input source
- Fixed problems with window positioning
- Fixed @mention streaming with tweets indirectly addressed to you
- Spaces behavior improved
- UI tweaks
It's thought that secret backdoor violated Apple developer guidelines and that is why its being removed. MacHeist members who purchased the Tweetie 2 beta access may want to stick with 2.0 for now.