v2.5 is a massive update for the base game. Unfortunately, the update was so big that we were unable to support old save games. To make up for this, we are making v2.33 available for all players as GalCiv3 Classic so you can keep playing older save games. The process for accessing it is similar to opt-ins:
- Select 'Galactic Civlizations III' in your Steam Library list
- Right-click and select Properties
- Select the BETAS tab
- From the dropdown, select "GalCiv3Classic - v2.33 release" and click Close (if you don't see this option, restart Steam).
Steam should pull down the changed files; if you ever want to go back, do the same as above but select default.