Build V8.1 is just a collection of bugfixes related to V8 that have been reported to us. The biggest one is the fact that you can now reselect the resolution of the game.
V8.2 is due towards the end of this week and will contain the Research tree and ground combat Save / Load features, plus any additional bugfixes that are required.
Patch notes below (other changes have also happened but are not listed):
Re-added the resolution changer box - you can now choose what display size for the game to run in.
Main title screen images updated.
Aircraft cannon images updated.
UFOs now disappear correctly from Geoscape when escaping to space.
Deprecated short range radar graphic removed from the Geoscape.
Commence / Resume operation text is now clickable on the title screen, rather than just the checkbox.
Quitting a game now takes you to Main Menu rather than desktop.
Save game now also saves on pressing Enter after typing a game name.
Double clicking on a save in Load Game screen loads it up automatically.
Save games must now have unique names.
Aircraft weapon slots are now labelled with their type - Normal, Heavy or Cannon.
Aircraft can now Tail UFOs (and also tail them until they are over land)