Launch day for Wealth of Nations is coming up fast! But even if you wait to buy it, your current installation of Europa Universalis IV will be greatly changed for free because of a new patch - we hope you’ll find these changes are for the better.In this, the tenth developers’ diary for Wealth of Nations, we will be looking at the various changes and improvements that we have made to mechanics and balance, all of which will be part of the free 1.6 patch for Europa Universalis IV.We have changed how nations gain Aggressive Expansion in 1.6. Previously, vassalizing a nation would give a fixed amount of AE regardless of that nation's size, while taking its provinces would give AE for each province captured. This has been changed to be more consistent; vassalization now gives AE based on the number of provinces held by the country that is vassalized, though the AE gained from vassalizing is still lower than that you would get from conquering. A number of ideas and policies have also gained a new modifier called Aggressive Expansion Impact, which lowers the amount of AE you take from signing peace deals. Additionally, breaking a truce now always gives a large amount of AE, even towards your allies.Unit types have received a comprehensive rebalance, with almost every single land unit in the game having their stats changed. The overall number of 'pips' on units were cut in half to reduce the role played by technology in land battles. Major rebalancing was also done of the different technology groups, who are now almost entirely equal in overall strength, but 'peak' at different times. For example, the Ottomans receive very strong early game units, but aren't as good in the late game, while Western units start out poor but excel in the late game. Progression through units is now much less uneven for many of the slower tech groups, and many units that were under- or overpowered for their tech level have been adjusted. The African and Native American tech groups also received a number of new cavalry units.As a part of these changes, nations that Westernize will no longer get Western units, retaining their old technology group's units instead.Rebels have been made into much more of a threat in 1.6, spawning in greater numbers and with better army composition. Newly conquered territories will now also be a source of turmoil, as Nationalism will remain for 30 years even if you core the province. Since this makes traditional conquest harder and diplomatic annexation even more attractive than it already was, we are also introducing a cost to diplomatic annexation.When you start to diplomatically annex a country, doing so will have a ticking cost of up to 15 diplomatic points per month. When your point expenditure reaches the country's total base tax * 15 (so a base tax 10 country would take 150 diplomatic points to annex), the country will be annexed. This means that diplomatic annexation is no longer a 'free' alternative to outright conquest, but uses a different kind of points and allows you avoid all the nationalist problems you get from just taking the provinces.We've noticed that the early colonizers such as Castile and Portugal often get a massive advantage just from being early, quickly locking up large parts of the new world before nations like England, the Netherlands or France can reach it. To slow down early colonization and give the later colonizers a chance to compete, we've tied the base settler growth to diplomatic technology. At level 3, this base growth is only +25 (compared to +50 previously), but increases at tech levels 10, 15, 22, 26 and 32 up to a total of +150, allowing for rapid colonization in the later stages of the game.Another addition to technology is Administrative Efficiency, a new country-wide bonus that is unlocked at administrative technology level 23 and increases at 26 and 29, up to a total of 75%. Administrative Efficiency directly reduces the impact of province base tax on overextension and warscore cost, allowing for much larger territories to be conquered at once. Additionally the scaling of core time from country size has been removed - all nations now core provinces at the same speed regardless of size (but it is still affected by factors such as culture, religion, having a claim and so on). This creates a more interesting late game, as the large nations that have formed by then are now able to score decisive victories over their rivals instead of fighting 10-year wars over a few border provinces.Finally, the neighbour bonus multiplier to technology has been reduced from 5% to 2%, meaning that it is less of an ideal strategy to hold off increasing your technology level so that you can stack up neighbour bonuses and more cheaply advance.In dev diary 5, we talked about the changes we made to the Reformed and Hindu religions but failed to mention a change to the way Religious Unity works. Up until now, Religious Unity has simply been a factor of how many provinces of your national religion you own, making tolerance rather useless since having lots of tolerated heretics and heathens would tank your Religious Unity anyway. We have now connected Religious Unity to how tolerant you are towards the religions in your provinces.The effects of tolerance on religious unity per province are as follows:- Religion you have negative tolerance towards: 0% unity value- Religion you have 0 tolerance towards: 25% unity value- Religion you have 1 tolerance towards: 50% unity value- Religion you have 2 tolerance towards: 75% unity value- Religion you have 3+ tolerance towards: 100% unity valueProvinces of your national religion always contribute 100% unity, regardless of your tolerance towards your own faith. This means that if half your country is your national faith, and the other half is a faith you have +1 tolerance towards, your total Religious Unity will be 75% instead of 50%. Additionally, the events that fire when you have positive tolerance of heretics which convert your provinces to heretic religions are now far, far less likely to occur.As mentioned in Dev Diary 8, the building system has received a comprehensive overhaul, with many buildings having their bonuses reworked. The aim is to make Government buildings more attractive, and clearly define roles for each line of buildings:- Government: Tax Income & Revolt Risk- Trade: Trade Power & Income- Production: Production Income & Cost Reduction- Military: Manpower & Land Forcelimit- Naval: Ship Building & Naval Forcelimit- Forts: Defense & Supply LimitThe AI has received its usual slew of improvements, particularly in the areas of naval warfare, trade and budgeting (as well as plenty of bug fixes).In addition to these general improvements, some work has also been done to make allying with the AI a better experience. First of all, the importance AI places on trust has been increased considerably, with AI nations much less likely to turn on a highly trusted ally. The way you make the AI trust you has also been reworked - it's no longer enough to be allied for a long time, you have to actually fight in their wars and give them things they want in your wars if you want the AI to trust you. If you actively work to help your allies, they will be more likely to stick by you when the going gets tough.Additionally, a new opinion modifier called 'Wants your provinces' has been added, which scales according to the amount of land you own that the AI would like to own, and with the importance they place on that land. Additionally, the AI is now much less likely to turn hostile against a nation they have a high opinion of, and will never go hostile against a nation they have more than +100 opinion of. This will show you exactly why an AI nation is hostile towards you, and will cause them to behave more logically; an AI nation that likes you a great deal won't break the alliance just because they want a province or two from you, but if they're looking to take everything you own nothing will push that opinion into positive numbers.If you've ever felt that it is a bit silly that Tangiers is considered a distant overseas province to Castile, we have some good news. The way we calculate overseas provinces has been changed so that provinces within a certain distance from your capital (roughly the distance between Italy and Libya) no longer count as being overseas provinces, allowing you to get the full tax, manpower and forcelimit benefits from those provinces.We have also overhauled the way that Goods Produced scaled in relation to a province’s base tax. Before 1.6, each province produced a base of 1 + base tax*0.01 goods. So, a 10 base tax province would produce 1.10 goods - only slightly more than a base tax 1 province’s 1.01. This has been changed to a simple base tax * 0.2, meaning that a 10 base tax province will produce 10 times the goods of a base tax 1 province - a much more meaningful difference between a rich and poor province.As a final bonus, many nations have received tweaks and improvements to their Dynamical Historical Events. We felt that too many DHEs had trigger conditions that are near-impossible to achieve, are set to fire only in tiny windows of time (with a high mean time to happen too), or simply offer choices where one option is clearly superior to the others, removing any real sense of fun in playing out alternate histories. Austria, Ming, the Netherlands and Poland have had their DHEs significantly improved so they will be more frequent and interesting. And, of course, we've even added some new events, too.