TS2353: 'slack' does not exist in type 'MessageRecipient' (@trycourier/courier)
The Recipient type was missing the slack property (it existed in UserProfile but was not carried over to MessageRecipient), so the documented send shape failed type checks. The maintainer confirmed the miss and shipped the corrected typings in @trycourier/courier@6.0.7. Upgrade to 6.0.7 or later. Source: htt…
Problem outcome: unknown