Possibly the most exciting thing to work on in this version of MadelineProto was the new update management system: I whipped it up in merely two days a few weeks ago, and it has absolutely improved the overall reliability of MadelineProto.
Huge thanks to Aliaksei Levin, the developer of tdlib, for explaining to me how exactly does the MTProto update API work: he saved me a lot of time, and was really nice <3<3<3.

While thinking of an easy way I could implement the new update system, I had an inspiration:

I created a unique, reliable, fast and extremely simple update handling system based on MadelineProto's loop API, not present in any other MTProto client, not even tdlib.

Instead of messing around with various synchronization locks, checks and cluttered update receivers, I implemented three simple feed loops.
Updates are fed to the first update loop, where some simple duplicate/hole checks are done.
Updates are then fed to a second update loop, where secondary duplicate/hole checks are done.
A third loop type takes care of eventual holes and periodically fetches updates for all supergroups, channels.

All of this is implemented without any kind of additional synchronization or locking due to the nature of the MadelineProto loop APIs, with 1% of the complexity of the official clients (which means less bugs and more pony time for me).