The first change in the Twitter API is active since a few days, what means, that third party clients has only periodical access to several APIs (Site Stream and User Stream) this week, which will shut down finally on 08/23. The DirectMessage-API may exist until 17th of September and one week before there will be the new API-Restrictions and new rules for the development of apps come into effect, which will make it even more difficult for the unofficial clients.
Sure you can beg to the support team, that your own app become the actual limits, but this is so nicely worded, that the exception is only for the actual version of the app. If there will be a new version e.g. of Tweetbot there will only be the new limits in effect. And this will become the end of Tweetbot & Co.
I have not really a clue, why Twitter is behaving in such a way and ignores the wishes of their users. I think, it is about the maximizing of advertising income and paid tweets, they don´t show in the 3rd party apps. Twitter seems to be orienting on Facebook, when it comes to reshaping its streams. The in the beginning chronological timeline in the webview and in the official app was destroyed because of algorithms and advertising, so that they are unusable.
I have a look on Mastodon since a few days, which have a comparable concept like Twitter, but is only a piece of software in the first place, that can everyone use to build your own instance. The Mastodon-Instances could communicate among themeselves, but could be blocked, if there is an instance that send spam.
The idea behind is tempting and the many instances of Mastodon were overrun by opening accounts after the announcement from Twitter. Nevertheless are there too few users on the instances at this time, so that there is a comparable feeling like with Diaspora. Diaspora was born with a similar approach against Facebook back then, but have in the time of nearly eight years since the beginning not break the marking of more than one million users.