From the news section of their newly designed website:

We are also working on getting major updates to Tweetbot 3 for iOS out. This will include landscape mode for iOS (finally), and the highly anticipated update to the iPad version. We plan on putting a lot of time and love into making Tweetbot a better product this year.

They’ve removed Convertbot and Pastebot from the App Store, as Convertbot’s functionality has been rolled into Calcbot and they don’t currently have the time it would require to update Pastebot for iOS 8. They’ve also decided to reduce Weightbot’s pricing to free.