None of this is mentioned in the Patch Notes and has ever been on PBE.
I've put together a video showcasing all of the undocumented changes that I've found.
* E's stun duration now lasts 0.25 seconds. It normally lasts 1.25 seconds. It now lasts as long as an Aatrox Q.
* You gain a Turret(Q) charge upon respawning. This can bug out if you already have 2 Turrets as you respawn and you can end-up holding 4 Turret Kits.
* R+W and W no longer share a cooldown. This means that you can R+W, even if W is on cooldown.
My guess is that these changes are a subset of some other Heim changes that haven't been revealed yet and managed to sneak their way through to live. Unless he gets disabled / hotfixed quickly, you can go and try all of these out right now.