Sorry Petr, no improvement for me. RC4 on PaleMoon is still broken - Avast appears to re-write it to something not understood: "(Error code: SSL_ERROR_NO_CYPHER_OVERLAP)". This is the same error one gets if RC4 isn't enabled in the PaleMoon prefs.js.
Also "self-signed" certificates (and special ones like
https://www.fnmoc.navy.mil and others!) saved in PaleMoon now become invalid across OS reboots. OS is W7-64+ESU. Firefox works fine (except where RC4 is required -- hence the use of PaleMoon just for some local hardware access).
I can live with the lack of RC4 - just turn off Avast for the few times I need access to the LAN device that needs it, but the certificate problems are going to bother anyone using PaleMoon (and maybe other non-mainstream browsers?). I also tried older versions of PaleMoon -- same issue. Avast 22.9 is what's different.