Here are Itchio's compatibility guides:  

https://itch.io/docs/itch/integrating/updates.html 

https://itch.io/docs/itch/integrating/compatibility-policy.html  

Please use a supported method, so updates can be downloaded directly through the app.

I'm unsure what you're referring to, since all builds on Itch are hosted on Itch, not other download sites...