In December 2012, Twitterrific 5 was released for iOS devices. (...) The developers have noted that the 5.0 update for Mac is facing big delays.
So what’s going on here? Why has it taken two years for any more news of the update? When will the new version finally be available?
The unfortunate truth? Not even the developers know. - 9to5Mac
Good article on the current state of third party Twitter development on the Mac