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In case you missed it, there are now several #RetroComputing Mastodon apps available:
Apple II
https://www.colino.net/wordpress/en/binary-release-of-mastodon-for-the-apple-c/
Apple Macintosh OS (pre-OSX)
https://github.com/smallsco/macstodon
Commodore Amiga
https://github.com/BlitterStudio/amidon
IBM MVS
https://github.com/mainframed/BREXXTODON
MS-DOS
https://github.com/SuperIlu/DOStodon
Windows 95
https://github.com/meyskens/mastodon-for-workgroups
@feditips are there any for the #atari8it or #zxspectrum?
Not that I know of, sorry! 
By the way, if you're interested in 8-bit retro computing you might want to follow @reenthused which I highlighted over on @FediVideo today. The account posts lots of 8-bit and 16-bit computing videos, you can browse them all at https://diode.zone/a/reenthused/videos
@feditips @reenthused @FediVideo thanks, will check out the links. It's been a while since I looked in detail at the retro scene.