I'm sure this is on here, but could someone point me towards a mod that allows users to select to receive PMs by email on Threads V6.4.2. I can see the mod for later and earlier versions, but not this one.

Thanks !

Should be nearly identical, I don't think much changed from 6.3 - 6.4 regarding pm's. Start looking here:

https://www.ubbdev.com/forum/modindex.php

Yes, the version for 6.3 should work with 6.4. Minor changes may be necessary and the lines may differ, but basically, it's the same.