New starbase module: "Ascension Gate Study." Allows the player to get a lot more out of the Ascension Gates.
I haven't made it to this yet, but you seem to be continuing to confuse Ascension Gates and Ascension Crystals. An Ascension Gate is built on land and is used for a Research Victory. There is no way one can be studied by a starbase module. Ascension Crystals are in space and must be researched by starbases with the appropriate modules to get enough Aura points to ascend and get an Ascension Victory.
We've made a substantial improvement in performance. This boost is especially noticeable in the shipyard screen and in late-game turn times.
I've played several games starting with the first 3.81 opt-in and continuing to the 3.9 release. The AI turn times seem to be quicker early in the game and are definitely a lot smoother. By smoother, I mean the game doesn't have the situations where 4 or 5 races will finish in a fraction of a second, then one race will take 3 or 4 seconds, then several more will be fast, then another will take 2 or 3 seconds, then the rest of the AI will finish. All of them seem to take the same 1 or 2 fractions of a second until the turn is finished very quickly. I haven't played a full game because of all the updates, but I noticed that I was getting a lot more turns played than I expected for the amount of time I played. I also was playing longer at a time because the AI turns were finishing so quickly that I felt I had to do "just one more turn." This may become a problem, but it's one I'll be glad to have.
Surrender change: Surrendering players now destroy their worlds upon surrendering unless they are surrendering to a particular player in which case they will transfer their homeworld (and only their homeworld) to that player.
This works except for one irritating problem. All the planets that are turned into dead worlds retain their icon showing the race that used to own them. The icon stays until the game is saved and reloaded. This is what happened when the Mu'Kay surrendered to the Tywom.

All territory in a player's ZOC is always visible. No fog of war (in your borders).
The problem with this is that when my influence expands the visibility does not. It takes a ship moving into the area to make the visibility update. The ship doesn't have to actually move into the area that isn't showing visibility, it just needs to get close enough to make the game update. Despite the lack of visibility, if a foreign ship enters my influence, I can see it even if the visibility isn't correct. It's just the visibility appearance that's the problem, not the ability to see foreign ships. It may be necessary to play on a larger galaxy to see the problem. I have videos showing this, but they aren't where I can provide a link at this time.
AI evaluates foreign influence before determining whether a planet should be colonized.
This didn't work right in one game I played with one of the opt-ins. There was a planet ready for colonizing in my influence at the end of my Turn 99. An AI settled it before the start of my Turn 100. During Turn 100 my influence was 22.6 times their influence. Before the start of my Turn 101 the planet flipped to me. I have plenty of screenshots showing this. Unfortunately, I don't have a save. I haven't had situation like this again, so I don't know if it still exists.
I found a new problem in the opt-ins that I think still exists. AI ships are ignoring solid objects in the galaxy. I saw an AI ship attack the ships stationed at an enemy planet by moving through a dead world to get there. I then saw other cases where a ship stopped on a solid object. One was a colony ship stopped on top of a planet it was probably trying to colonize.

Another colony ship was probably trying to colonize the same planet but couldn’t because the other ship was in the way, so it was stopped on a star.

I also found a freighter stopped on top of an Ascension Crystal.

Despite all these little problems, I enjoying this update. The improvement in turn time is a very welcome improvement. I'm worried I'll be spending more time on the game than I usually do. I'm making all the reports that I do because I want the game to be even better than it is.
Which leads me to the next part. The AI can be really dumb at times. While playing the first opt-in I saw AI ships doing some strange things. The AI was unable to do anything useful with its ships as it seemed to be caught in a loop. Because I had a good view of what the AI was doing, I got some saves while this was happening and probably before it started. I need to verify some things, then I'll make a separate post in the Support section with links to the saves. The strange things are not the same as in this post, but I did see that happening in several of the games I played, including the 3.9 release. If these two problems can be fixed, I think the AI will be a lot more dangerous.