Anthropic’s current migration guide says the earlier Claude in Slack experience stopped answering in channels of paired workspaces on October 5. A channel still configured as Legacy receives a retirement notice until its version, or the version it inherits, is changed to New. The documentation says direct messages are unaffected by this retirement.
The scope matters: this is not a claim that every older Slack installation stopped working. The guide describes different behavior in unpaired workspaces. It also warns that personal GitHub access and other connections do not carry into the new shared agent identity automatically. A migrated channel can therefore need explicit tool setup before code work succeeds.
Editorial take: Treat this as a migration check before treating it as an outage. Teams should establish whether the workspace is paired, inspect the channel’s version, and verify its connections. The visible @Claude handle staying the same can otherwise hide a meaningful change in who the agent acts as.