Puma phased restarts

Affected components

  • AppSignal for Ruby gem version v2.9.17 and later (see workarounds).


We've added a new plugin to add our Puma magic dashboard in version 2.9.17 of our gem, which breaks Puma phased restarts.

See appsignal-ruby issue #575 for more details on the specific error.


The AppSignal integration stops, but is not restarted when using Puma phased restarts.


  • Downgrade the AppSignal gem to 2.9.16 until the issue has been resolved.
  • Do not use Puma's phased restart feature until the issue has been resolved.