We recently have had a need to convert from the old slack webhook methodology to a new method of connecting Slack and Salesforce. 

We have successfully setup the webhook and messages are flowing to the designated channel, but this is not emulating the behavior we had in the past.

Previously we had used the @Invocable method to call from Process Builder or Flow the channel that we wanted to post the message to, and this allowed us to distribute the incoming message away from the central webhook channel and to the desired channel (for which we have ~15-20 bot channels).

The method used mirrors the one in this article:https://medium.com/@sfjimmyjay/salesforce-to-slack-integration-1448b10d4f73 

With this new webhook the distribution is no longer successful and all the messages intended for these channels are flowing into the webhook channel exclusively. 

I have added the app to some of these channels to see if that was the problem, and that did not resolve the issue. 

Would appreciate anyone's thought or feedback on what I might need to change in terms of my methodology (should I not be doing this through a webhook any longer?), updating the code to allow the distribution to flow again, or what else I might need to do to get back to the previous functionality. 

Thank you!