What caused this sudden huge update? The only update I saw from poe were new supporter packs.
The latest client patch didn't trigger the update; the decision was made at the start of August with the TW server beta test.
The original design, and how the EB API has worked up until this point was based on things that work in other games, naturally. As time has gone on, and we've had to do a lot of changes as a result of the PoE client changes, it's becoming more and more apparent, the majority of the stuff that is done in other games simply doesn't work here in PoE. A simple example, is when people ask why you can't chat and do other stuff in game while botting in PoE, yet you can in D3. Things that can be done in D3, can't be done in a game like PoE, or even a game like Hearthstone, for example (which I only bring up since it's a commonly asked thing).
The API for Beta has been updated quite a bit compared to the Release version, but one aspect did not really change. That's how we interact with the client, because that's the core means of the bot working in the first place. What sparked the immediate rewrite of all this stuff was a combination of a lot of things really, but the most important was that things were happening with some test code that shouldn't have been (to be specific, client crashes when not using anything specific to PoE). Upon looking into the cause of the issue and why it was happening, a better method was discovered to make the bot work (hopefully, of course, we won't really know until everyone is using it again). Switching to this method changed all input related stuff, but the decision to change everything in the API was more of a combination of the flag issues popping up again, how long it takes to update and maintenance the current API, and other things that from a risk/reward perspective, are no longer in the reward favor, in terms of design.
It's not a secret what is actually being changed, since you guys will have it soon enough, but basically the API will now only utilize input emulated actions for everything that requires interacting with the client. For example, if you want to level a skill gem, you gotta open the inventory panel and click the button itself (main screen support might be added later). If you want to logout, you have to bring up the ESC menu and click the respective button to logout. Equipping a skill gem means picking up the item to the cursor and placing it over the correct slot and clicking. Etc...
The API will do most of the hard work for this stuff, but it does change how all logic has to work as a result. On the plus side, we do now have more access to information to things that was otherwise not possible using the previous API. For example, we never could get the buy price for an item in the shop, because it was calculated at runtime, and then stored to a gui element. There was no other place the information existed, so we never could do proper buying support. With the new design being worked on right now, I already have example buying code in place that works, and supports getting the cost of items. There's some other cool stuff that can be done, but basically the entire mode is being changed to hopefully be able to support new features as the are added faster, and avoid random issues that have otherwise been plaguing the bot for a while now.