Hello everyone! 1.3.10 is our final beta patch before 1.3 beta goes onto the stable branch. It makes some changes to diseases, as well as some further adjustments to institution spread.
Checksum: c764
Date: July 07, 2026
Previous Patch: 1.3.8
Society
Using the cabinet action to assimilate Primary Culture pops with a non-primary culture is now correctly much slower, instead of being the same fast speed as Discriminated cultures.
Diplomacy
Enforced an alliance-style opinion floor and at-war block on defensive league joins.
Military
Reduced levy food consumption so early-game levy armies can sustain themselves without supply trains.
Capped the over-supply-limit food consumption penalty so large stacks no longer drain full reserves in days.
Geopolitics
Locations with pops migrating in no longer cause diseases to continue indefinitely.
Advances
Moved levy, ship, military, and production advances out of the free age 3–6 trees.
Institutions now spread from the birth location to the market center at a base of +1% each month.
Increased the friendly-neighbor institution spread rate (0.020/0.010/0.005 → 0.040/0.030/0.020).
Stopped blocking achievements when Could-Have-Spawned Spread Gamerule is enabled.
Other
Made HRE Rank Restriction achievement-blocking.
Situations
Hussite Wars: The Plight of the Hussites event (hussite_wars.7) option A now creates an alliance with Bohemia if possible.
International Organizations
Fixed an issue where the AI would flood the Emperor with the Imperial Diet petition.
Events
Made AI Scotland much less likely to convert to Gaelic culture during the opening events.
Fixed the "Rise of Timur" situation (flavor_tim.8) not firing because the Chagatai Khanate and its vassals use Mongolian culture, which was not included in the Turkic/Iranian culture group check.
Government
Fixed the Genoese "Diarchy Republic" unique government reform incorrectly applying a character-scoped modifier by replacing it with +10% Cabinet Efficiency, and the reform's description showing the wrong country name after forming a new country.
Corrected the formable tier of TUR_f (Ottomans) and RUM_f (Rum) to be Tier IV, on the same level as Byzantium (BYZ_f), which was the original design intent for the three of them.
Economy and Production
The Merchant Guild Chapel building is now correctly available only for Building-Based Merchant Republics.
Triggers
Fixed an issue where the "is_parent_of" trigger would always return false.
Allowed game rules to be changed mid-game in multiplayer.
Bugfixes
Fixed a crash related to the map line manager.
Fixed a crash related to antagonism.
Fixed a crash related to pop conversion.
Fixed a crash related to the filters in the mercenary captain selection screen.
As usual, here is a list of handy EU5 links:
Be Ambitious!