We released Godot 3.5 in early August, and like any release, there are few rough edges to iron out which warrant making maintenance "patch" releases (3.5.x). Such maintenance releases focus on fixing bugs and not on integrating new features. This helps guarantee that the overall production readiness of the stable branch keeps increasing.
So this 3.5.1 release fixes a number of regressions that users reported after the release, as well as various other fixes to pre-existing bugs and usability improvements.
This is a safe and recommended update for all Godot 3.5.x users. It should have no major incidence on your projects, even complex ones in production, if you're already using 3.5-stable.
As usual though, if you need to go back to the previous 3.5 version (3.5-stable), you can use the stable-3.5 beta branch in the Steam settings for the application.
Read the release blog post for details on the changes.
The illustration picture is from Dome Keeper, an innovative roguelike survival miner with gorgeous artwork, developed by Bippinbits and published by Raw Fury. It was just released on Steam and the first players seem to love it, check it out!
https://store.steampowered.com/app/1637320/Dome_Keeper/