The environmentalist in me wants to say to unplug any used hardware devices, the technologist in me wants you to leave it connected so we know the health and that is is running the latest software.
You should be fine either way.
We did have a firmware issue regarding time synchronization that has been rolled out to every controller that is currently online. If there are controllers that haven't been online for quite some time (6 months?) they might have to remove and re-activate the controller. This will be a very, very small number of our overall controller footprint.
Hope this helps.