This disables calling in your allies, but allows you to call in your protectorates.
If the demand is accepted, the province is yours, otherwise war ensues.
Estates that grow extremely powerful will attempt to seize power in the country or break away to form their own nation. A powerful estate will have significant effects on the country that are good or bad depending on whether they are loyal or not. Estates have a loyalty and influence level, and can control territory, granting various benefits at the cost of local autonomy.
Favors are gained by being allies and helping each other in war, and can be used to raise Trust or to call them into your wars. Here you can set your attitude towards other nations, see what provinces they are interested in conquering and see their Trust towards you and the amount of Favors they owe.
Patch 1.14 was released on 1 December 2015, coinciding with the release of The Cossacks.