Read the full patch notes here.
MAJOR CHANGES
- Major map revisions and additions: East Africa, Armenia, Central Asia, Siberia and India
- Added Steam matchmaking support
- Added Steam workshop support
- Added diplomatic range, blocking diplomacy and councillor actions vs too distant characters
- Factions will now revolt as a single unified realm under a temporary title
- Added attrition for units that have been "out-of-supply" for too long (can't live off the land in neutral counties, etc)
- Added support to change window mode setting: fullscreen, borderless or windowed
- New unit type system allowing for more flexible unit types, including War Elephants, Camel Warriors and Horse Archers
- Blocked "North Korea Mode"; you now lose huge parts of all income and levies if your demesne is too big
- Save games are now compressed by default (can be toggled on and off)
- Major memory and performance optimizations
Edit: Since we've added several major new features in the patch, old saves are no longer compatible. There is however a workaround if you wish to finish your old save, or play with mods that have not yet been updated.
- Right-click on your game in your Steam Library
- Select Properties
- Go to the Beta tab and select the 2.0.4 version in the dropdown menu. New DLCs will not be available in this version for comaptibility reasons.
- To revert this, go to the beta tab again and select None in the dropdown menu.