I am happy to tell you that as of today you are able to programmatically trigger Assembly replays and Notification replays. Both functionalities are now available through both website and API calls.
Please read details about them here.
It's now also possible to pass custom variable into your Assembly Instructions by attaching a key
fields to your Assembly hidden
params field's JSON.
Please read about this here.
And another one that plenty of people have been waiting for: On the Assembly page you can now see how much the Assembly cost you in terms of data towards your plan