Link for SF13 for you:
https://stockfishchess.org/download/

This from lichess:

https://lichess.org/blog/YCvy7xMAACIA8007/fat-fritz-2-is-a-rip-off?fbclid=IwAR1i...

The suggestion there is that Albert Silver is knowingly entirely dishonest in his claims for Fat Fritz 2. 

And has been systematically dishonest through the whole time of Fat Fritz and Fat Fritz 2.

And that Chessbase are too. That saddens me.

IsaVulpes wrote on 02/17/21 at 02:56:38:


With my IT skills being pretty limited I have always found the Chessbase staff to be extremely patient and helpful so I'm a little bewildered by the "passed left and right by upstarts" comment. That has certainly not been my experience and lord knows I have hounded them enough for help over the years.

I have used Google a bit and read slightly odd thing that the version of the net that is on Github are weaker than the version of the net in the commercial product....

I don't think "everything" about ChessBase is a joke. ChessBase is not only (Fat)Fritz. They do some things right, but also they are making some obvious and serious mistakes. Also, I am not a lawyer (standard disclaimer), but it's not clear to me the net has to be released at all. Something for knowledgeable people to explain. I have to wonder who is making the decisions about Fritz, and Houdini (news to me), but it's all the same "department". Maybe it's simple ignorance, maybe it's getting bad advice, maybe whatever. The somebody inside ChessBase with the final say should know better.

proustiskeen wrote on 02/15/21 at 02:53:27:

"Selling Stockfish derivatives is possible with the GPLv3 license we grant, but not without requirements. In particular, the license states that if one redistributes a program derived from our work, the corresponding modifications of our sources and all information needed to build that program must be made available. Only after explicitly informing Albert Silver (the author of the net in Fat Fritz 2) of a license violation have matching C++ sources, but not the net weights, been made available. "
- https://blog.stockfishchess.org/post/643239805544792064/statement-on-fat-fritz-2

Everything about FF2 is ethically garbage. 
The jury is out whether it is legal at all, they are -as of now- effectively breaking the GPL licence, at the very least in spirit.

"soon, I think" is obviously too late. 
If someone is telling you 'You can sell this, but only if you tell everyone you got it from me', you can't start selling it and wait a month (or however long) with telling people. That was the precondition. 
If the net has to be released to the public before you start selling (that is how I understand it), then every cent that they made from Fat Fritz up until actually releasing the net is grounds for calling a lawyer.

Not that this type of behavior by ChessBase should surprise anyone -
June last year, they published a long sales pitch for the entire Houdini series https://en.chessbase.com/post/10-years-houdini ; this is 2 months after https://chess.stackexchange.com/questions/29181/is-houdini-6-a-stockfish-clone this thread clarified that the entire engine is stolen (on talkchess, the discussion had been running for a while prior).
It is still for sale at full price in their shop https://shop.chessbase.com/en/products/houdini_6_pro_multiprocessor_version . 

Everything about ChessBase is a joke. A company stuck in 1995, passed left and right by "upstarts", that now tries to save itself from the onslaught of modern chess tools by selling stolen content.

ReneDescartes wrote on 02/16/21 at 00:01:52:

You might have to build "FatFritz2" from source. They changed the net size from 256 to 512, so I think the net is now incompatible with the Stockfish build. Okay I don't know for sure, but I think that might be the case.