They should send messages directly to their customers as a first step in addition to posting an official article on their site. That’s the minimum. If they haven’t done that then it is hard to defend.

Beyond that, Twitter is the de facto default dissemination vehicle, due to its reach. Even if people are not on Twitter, they are likely to see things from people that are on Twitter.

It's certainly not the right platform. It'd be one thing if they had any official communication on the matter anywhere else. Maybe they're ashamed and are trying to limit the visibility while only technically issuing an announcement.

They announced this exclusively on X.com, which ranks barely above Pinterest in terms of usage. That's below Reddit, Snapchat, WeChat, and Instagram, and requires a user account to view profiles and posts. And that's ignoring all the reasons X is a divisive platform with an extreme political bent.

GitHub chose not to announce this on any other social media either (BlueSky, Facebook, TikTok, YouTube, LinkedIn, or Mastodon, as of this posting, and with no emails sent on the matter.)

It’s a very popular messaging platform for tech enthusiasts.

Probably the best option after sending a mass email when customers need to take action. The status page is for reliability issues impacting end users & the blog is for in-depth analysis.