Learned about Gemini today from various fediverse users mentioning it in their profiles. I wanted to use the emacs client elpher to check it out, but it required emacs version 26.2 at the minimum, but my version from Debian's repos was 26.1, so I built the latest version of emacs from source and fixed a few incompatibilities between my init file and version 27, and now I'm in!
@tzerenij Strange, I wonder what happened. The only explanation I can think of is that I hadn't switched from melpa.milkbox.net to melpa.org. I only discovered that melpa.milkbox.net wasn't working anymore after I had already upgraded to emacs 27, so maybe what actually fixed it was just fixing my melpa