If you’re a frequent user of Twitter for Mac, you could be in for some bad news. According to MG Siegler, he tweeted that Twitter for Mac has ceased in development and that the client will no longer be updated. Given that the last update for the app was back in June of 2011, it certainly does not seem surprising that this could indeed be the case. However interestingly the rumors have also suggested that Twitter had reportedly prepared an update that will make it compatible (aesthetically) with the Retina display MacBook Pro, but we’re not sure if those plans were shelved or if that will be the last update. Some have speculated with Twitter acquiring Tweetdeck, there is a chance that Tweetdeck could become the new Twitter for Mac instead, although given that Twitter has been integrated into the latest version of OS X Mountain Lion, perhaps a native client might have been seen as no longer necessary.