Stash is a UCI-compliant chess engine developed from scratch, licensed under the GPL v3. It is one of the most promising and developed chess engines in terms of strength increase.
Unfortunately, the author does not officially share the changes he made in the new version.
For comparison I present the ranking of previous versions of Stash.
It is worth noting that Stash very easily and without any errors can be compiled for Mac computers running on Intel processors.
Feel free to download the Stash 33.0 chess engine.