Potentially long running upgrade tasks on large instances
Release 2.20.0 features an upgrade task that re-encrypts credentials stored inline of tasks with the new Bamboo SecretEncryptionService (which replaces the deprecated EncryptionService). While the operation itself is quick, the upgrade task needs to check each task's configuration, which might take a while when upgrading a Bamboo instance with a large number of tasks.
Potential upgrade issue on remote agents
Bamboo might be unable to upgrade apps on running remote/elastic agents:
This long standing upstream issue had been resolved as of Bamboo 5.3. However, there seems to be a regression in Bamboo versions 5.6+, which expose a similar defect.
In case you are affected, this can usually be remedied by restarting the Bamboo server or disabling/reenabling the remote agent.
Please refer to our KB article Unable to execute task due to plugin not being installed for details.