This is a maintenance update that brings many bugfixes and AI improvements.
We're experimenting with changes to Spanish and Portuguese colonization: it is now possible for both countries to seize native lands in their Treaty of Tordesillas spheres, not just colonies of fellow Catholics. This will help Portugal get closer to its historical empire more often, as they have struggled in test games since 1.3.
We've rebalanced rebels:
Peasant rebels are now much weaker in the mid- and late-game
"Smart" rebels like the Dutch and American independence movements are now smarter - they can move to join an adjacent siege if they don't have enough forces to besiege their current location, and they can march across a less valuable province to attack a more valuable target.
Non-smart rebels also have the ability to march across a province to find a target, but only if there are no valid targets adjacent to their current location
We heard your complaints about slow diploannexation, and we've reduced the minimum time from 50 years down to 20 years.
We've also greatly reduced the speed of AI diploannexations: they are much less likely to annex within the HRE, or to annex vassals whose provinces are neither cores nor valuable.
There are also many other AI improvements, some hopefully noticeable, some not so much (like the AI not needing to cheat as much to keep up with you).
On the scripting/scenario setup side, we've added some interesting options.
First off, we've added the ability to set AI event choices to "ahistorical". This means if the AI receives an event with more than one option, it will pick randomly from all options EXCEPT the historical first option. In other words, you will never see Aragon inherited by Spain, you might see China focus on outward expansion rather than inward perfection, and you likely won't see the Netherlands or the United States form.
Other highlights:
Burgundy has received many new events, including a new pathway for a surviving player-controlled Burgundy to inherit or even form Spain in the 16th century.
England can now "win" the Hundred Years' War, rather than just staving off the "defeat" event.
China can now reject closure and follow the teachings of the Jesuits, just like Japan already could.
Early game Lithuania, newly Christian, can turn about and re-embrace paganism.
The Timurid Empire can now form Persia.
The religious orders (Knights of St. John, Teutonic Order, and Livonian Order) now have a permanent casus belli on all heathens.
And many other changes - see the full changelog for details!