---
fixes:
  - |
    Action heartbeat checker was using scheduler to process expired action
    executions periodically. The side effect was that upon system reboot
    there may have been duplicating delayed calls in the database. So over
    time, the number of such calls could be significant and those jobs could
    even affect performance. This has now been fixed with regular threads
    without using scheduler at all. Additionally, the new configuration
    property "batch_size" has been added under the group "action_heartbeat"
    to control the maximum number of action executions processed during one
    iteration of the action execution heartbeat checker.