Here's how technology works in Crusader Kings II as it stands right now: You set the focus for your entire realm to Farming, Legalism, and Tactics... then you ignore that screen for the next 400 years unless you click on it accidentally. The Old Gods (and the accompanying patch that everyone will get for free) is attempting to change that by making technology a more active system. The final dev diary goes into a little more depth on how this will work. You'll find the video version above, and some analysis below.
The best way to describe the new system is this: Duke-tier rulers and up basically serve as the fonts of technology for the world, and their advances will trickle out to neighboring provinces over time. These fonts are fueled by tech points, which you will be able to spend to purchase an advance in each of the 18 newly-consolidated technologies. Unlike the base game, you won't have a random chance to discover the next level of a tech over time, and tech focuses are out.
The way you generate tech points is based on buildings in a province and the liege's skill. Martial skill will generate more Militatry tech points, Stewardship generates Economic tech, and Diplomacy will advance your Cultural tech. The spread of each tech can be seen in the newly-skinned data layer, demonstrated above. Because if there's one thing we grand strategy players love, it's more data layers.
The other tidbit we got that hadn't been previously spoken of is the addition of "Steppe" provinces. Much of Eastern Europe will now be considered part of the Steppes, allowing Altaic and Magyar culture rulers to build the new Steppe Warrior Lodge and Steppe Riding Grounds improvements. These will ensure that their levies are more dominantly composed of mounted troops, as they were historically, since the default troop boosting buildings tend to be infantry-heavy.
As a bonus catch, it looks like the Steppe pagans are getting their own holding portrait art, instead of using the default pagan ones.
The Old Gods releases next Tuesday, and we're fairly sure we've extracted as much possible info as we can at this point without actually playing it. If you're hungry for more, sink your axe into our announcement interview , breakdowns of the first , second , and third dev diaries, details from the developer livestream , and the most in-depth Q&A about the expansion in all of existence .