This Development Diary, the last one before the release of The Old Gods, will elaborate a bit on the new technology system we are introducing to the game. We are including it for free in a patch, so you'll be able to make use of it even if you don't own TOG.
The original technology system in CK2 was not very rewarding or interactive, and thus the majority of people mostly or completely ignored it.
So since for The Old Gods we would need 200 more years of technological development we figured instead of trying to shoehorn that into the old system we could just as well throw most of it out and build something more interesting from the ground up.
Now all rulers of duke rank and above generate technology points in three categories based on their stats: martial gives military, stewardship gives economic and diplomacy gives cultural technology points. The ruler can then spend these to increase the technologies of their choosing in their capital. In addition to the stats, combat gives military points, universities give economy points and religious schools cultural points.
This means however that technology will only grow in the capitals of dukes and above, and for the rest of the world it will spread as usual.
The Old Gods and its accompanying patch has a few new buildings as well. Any holding by the coast can now build shipyards that produce galleys.
The horse lords of the Altaic and Magyar peoples will also have access to two special buildings in any castles they own in a Steppe province. This is a new terrain type that now covers most of the Eastern European plains. The Steppe Warrior Lodge and the Steppe Riding Grounds will take the place of the normal Barracks and Stables buildings in these holdings. They provide more cavalry at the expense of foot soldiers, to better reflect the tradition of mounted warfare the steppe cultures had mastered.
There are two merchant republics active at the start of the new 867 bookmark. The first is Venice, which should be familiar to most of you, and the second is Amalfi, a growing trading hub on the western shores of Southern Italy ruled by a collection of Greek and Italian Patrician families. As you can see from the screenshot, we have added a new province for this republic. It has an interesting if somewhat challenging starting position, given its close proximity to the Karling realms of Western Europe, the Byzantine Empire which still maintains a tenuous hold on the southern tip of Italy, and the Muslim lords using Sicily as a springboard from which to carry their conquests further into Europe.
That should cover most of it. The rest you will have to see for yourselves when The Old Gods is released on May 28th!
Bonus: Crusader Kings II: The Old Gods Video Dev Diary 3 - Technology