Since version 3, TeX has used an idiosyncratic version numbering system, where updates have been indicated by adding an extra digit at the end of the decimal, so that the version number asymptotically approaches π. This is a reflection of the fact that TeX is now very stable, and only minor updates are anticipated. The current version of TeX is 3.141592653; it was last updated in 2021.
It would be fun if they would never reach 3.15. Because of the pi joke. But semantic versioning has a say in this, too. Sadly.
This is what Donald Knuth is doing with TeX :)
Wikipedia:
There is also the mathfont of Tex, which slowly converges to e.
it’s fine, python releases don’t use semantic versioning
I would be childish and stubborn enough to actually do that.