Thanks for making this integration possible.
I tried this already by disconnecting my TTN devices from V2 on maker.allthingstalk.com, connecting to V3 and filling in all the required numbers and keys (dev EUI, dev Address, Network session key, Application session key). Also I copied the webhook address and filled this in on the TTN website.
Unfortunately I did not receive a message yet on AllthingsTalk. Did I overlook something? I could not find something in the given documentation.