It's easy to use lots of different versions of Rust nightly. Remacs requires a specific version. The https://autogen.sh/ scripts are admirably defensive, to help you get on the right version!
I've given up migrating my VPS hosts to newer distro versions. Instead, I'm trying to rebuild a new host with the newer distro version.
I'm slowly making all my server config reproducible and automated as a result :)
On the challenge of writing accurate source spans on Unicode source code: https://reedmullanix.com/posts/unicode-source-spans.html
Also (see footnotes) a fair number of LSP clients assume UTF-8 despite early versions of LSP mandating UTF-16!
I'm fascinated to learn that people are discovering weaknesses in state-of-the-art bots for playing Go, such that a novice player can reliably win: https://goattack.far.ai/human-evaluation
This suggests that self-play doesn't always generalise: it's not sufficient to beat earlier versions.