System notifications now sent from "Slack" user (USLACK) instead of Slackbot
BreakingBreaking change
This is a breaking change — integrations that rely on the affected behaviour will need updates before the change rolls out.
What changed
Slack system notifications (channel membership changes, User Group updates, Slack Connect alerts, retention policy notices) are now delivered from the "Slack" system user (USLACK) instead of Slackbot, and historical Slackbot system notifications will be backfilled/moved to the new DM. Apps that filter events by Slackbot's user ID, check the username field for "Slackbot", or expect system notifications to route through Slackbot must be updated to handle USLACK instead. This is tagged as a breaking change by Slack.