Here is a summary of the main changes introduced in the update:
Alliance Rework: Alliances are now true multi-national entities (no longer just bilateral agreements) with their own leader, chat, rankings, and laws. Joining and leaving are regulated by votes and cooldowns. Maintenance is now paid in Paper.
New Diplomacy: Introduces Defensive Pacts (ramping damage bonus when defending a partner) and Sworn Enemies (damage bonus in both attack and defense against a single target). Both require a daily maintenance cost.
New Resources (Wood & Paper): Wood is a new raw material, which is crafted to produce Paper.
Paper-based Economy: Money no longer fuels politics. Laws, battle orders, and party motions are now paid in Paper, and these costs scale proportionally with a country's development.
Party Ethics Rework: The old flat damage bonuses have been replaced by specific effects on the economy, diplomacy, and cooldowns. A new "Unethical" stance has been added (a mercenary playstyle that prevents the country from holding any diplomatic treaties).
Development Calculation: Introduces the concept of average development (the midpoint between core territories and currently held ones), which is now the baseline used to calculate political costs.
Government Announcements: Top government officials (President, Vice-President, Minister of Defense) can now post official announcements visible to all citizens.
Balancing: Bonuses provided by regional structures (Military Bases and Bunkers) have been halved for allied countries; they only remain at full strength for the citizens of the owning country.