* Upgrade license to GPLv3 for future license compatibility with some libraries
* Add OS and UAC compatibility manifests (emtee, iceman50)
* [L#1774502] Restore automatic downloading of up-to-date GeoIP databases
* Set cached hublists to expire in 24 hours, keep them longer only in case of download problems (emtee, rolex)
* [L#1979900] Prefer attempting outgoing connections on IPv4 when there's no IPv6 connectivity (emtee)
* Introduce the naming "Optimized" and "Legacy" for the 64-bit and 32-bit builds of DC++ respectively; the former gains advantage
  of modern OSes and hardware while the latter makes DC++ remain compatible with the 32-bit architecture and / or old hardware.
* Installer: detect available CPU features and offer the best DC++ binary for the current system (emtee)
* [L#1970416] Set the focus properly on the active window at startup (emtee)
* [L#1952754] Add new hublist server hublist.pwiam.com; blacklist and remove discontinued or inaccessible server addresses
* Add AboutConfig frame for testing and debugging purposes (iceman50, emtee)
* [L#1682791] Block possible unencrypted direct private message connection attempts (fix adapted from AirDC++) (emtee)
* Upgrade compiler for better performance; allows further optimizations to modern Windows versions (cologic, emtee)
* Allow copy of hub address with keyprint on secure hubs (code adapted from AirDC++) (emtee)
* Require SSSE3 for 64-bit builds (cologic)
* Documentation and translations updated as usual, thanks everyone