Avoid version 2.4.2
Since updating to version 2.4.2, Tweetbot displays weird patterns of mostly purple and black pixels instead of most pictures and also frequently crashes on startup. This happens both on a MacBook Air with macOS Sierra and on a MacBook Pro with OS X El Capitan. I strongly recommend skipping this build and waiting for the next one.
Other than that, this is and has been my absolute favorite Twitter client on both Mac and iPhone for the past few years. In other words, I would give a five-star rating for pretty much any other release.
UPDATE: I contacted Tapbots Support because of this issue and was advised to delete ~/Library/Containers/com.tapbots.TweetbotMac/Data/Library/Caches/ and then restart Tweetbot. As far as I can tell, this does indeed fix both issues mentioned above.
Lars Trebing about
Tweetbot for Twitter, v2.4.2