New release targeting .net 4.5.2. This is for new users to have an easier time installing, no need to install this if you already have it working.
Also, a "stunt" requested by a user to limit the mono threads to one per core is available, you may try this and compare performance or just stick with what is tried and true below. The "stunt" version is labeled with "1MONOTHREAD.zip" at the end.
EDIT: As of 2/24/2022, we have added experimental support for KSP2. Please note this may break at any time, but it works as of right now. Use the KSSL2 zipfile for this, and only for KSP2. KSSL_* zips are for KSP1.