Twitter is building a new native OS X app, the company’s Senior Director of Product Jeff Seibert announced at the company’s second annual Flight developer conference in San Francisco Wednesday. The app, which has been built for Apple’s latest OS X version El Capitan, comes with a number of new features, including support for private group messaging, and will be made available before the end of the year.

Seibert’s keynote was preceded by a brief but forceful appearance of Twitter CEO Jack Dorsey, who used his opening address to bow to developers, and ask them for forgiveness for past mistakes. “Somewhere along the line, our relationship with developers got a little bit complicated, a little bit confusing, a little bit unpredictable,” Dorsey said. “We want to come to you today, and first and foremost apologize for the confusion,” he said, adding that the company was committed to a reboot.

Dorsey went on to say that Twitter needed to get better about being transparent, and specifically called out Politiwoops, a third-party service built by the Sunlight Foundation that archived deleted tweets from politicians. Politiwoops was forced to shut down after Twitter turned off access to its data in May, at the time citing privacy reasons. However, Dorsey’s remarks suggested that the company may reverse its stance.

Dorsey said that free speech was a key part of Twitter’s mission: “Twitter stands for freedom of expression, and we will not rest until that is recognized as a global, fundamental human right.Perhaps channeling its inner revolutionary, he added: “Twitter is the most revolutionary communications tool of our time, and we want to make sure that we continue to build it, and make it great together with you.”

SEE MORE: Can Jack Dorsey’s Twitter Revolution Save the Company?

Twitter’s relationship with third-party developers has been rocky in the past. In its early years, the company encouraged developers to build their own apps and services powered by Twitter’s data. But over time, it restricted access to some of that data, and built its own tools and apps to replace some of those third-party services.