Tweetbot for Mac is now in beta. But in a move likely to make it an incredibly exclusive member club rather than the must-have Twitter app for Mac, if you aren’t already using it, forget it: you won't be able to play with the app until it is officially released.

In what is usually the reverse, the open alpha has become a closed beta because of Twitter's third-party app rules introduced in August.

"A lot of our Tweetbot for Mac Alpha users have worried about what’s going to happen to them now that the Alpha has been pulled," says the company behind the app on its official blog. "A few folks have suggested that we release a new version but without the ability to add any new accounts, we thought it was a good idea and have done that," 

Users who have already signed up will be prompted to download the new update.

According to the developers, the new update fixes several bugs, as well as adding features such as better keyboard support and improved profile view.