Back in the time, there was only a single way to ensure vital resources for your people: take from your neighbours by force. Does that mean that a zombie Apocalypse will certainly bring Mankind back to its dark age?
The answer is no, because, we've invented a new way to solve issues: Diplomacy. You should definitely give a try!
-With the 1.3.0 update, there is now a full Diplomacy system, that will allow you to interact more with other nations:

There are three agreement types:
- Non aggression treaty: Just ensure that both of you won't attack each other
- Mutual support pact: Agree to often send help to each other (military or medical). Also allow you to move unit and build structures through partner territory. The Fog of war is also shared
- Resources trade: Also allows gifts or resource requests to improve mutual relations
Remember that when you sign a treaty, you should not break it. Otherwise, other countries will see you as untrustworthy.
And some other changes:
-Fixed an issue that was making ambulances slower because of tech researches
-Fixed a multiplayer desync issue that was often occuring at the beginning of the game
-Fixed a UI bonus color in the policies tab
-Fix AI for nuke usage
-Fix a steam achievement
-Fixed a bug that was making a city/refugee camp neutral on some conditions
-Fixed an issue that caused trouble for joining a multiplayer game through Steam
-Fixed an issue with patrol in multiplayer mode
-Removed the old send resources buttons in multiplayer (now it's possible through diplomacy)
-Other fixes and small adjustments
No need to be scared by Halloween anymore! You know how to react if you are at the head of the state!
Changed files in this update