When the plugin starts after a computer boot or when the Stream Deck software is restarted, it does not know the current state of the external Midi controllers, and all buttons and dials are initialized with the value 0.

"Midi state restore" aims to restore the buttons and dials' states to more relevant values and (hopefully) mirror the states of the external controllers. The plugin does this by periodically saving the states of all Midi controllers to a disk file, reading this file at startup, and restoring the buttons and dials to the same state as at the plugin shutdown.

Please note that only the local state for buttons and dials is restored; no Midi commands are sent. If the Stream Deck software is being restarted quickly, this state is probably very accurate compared to the external controllers. If a long time has passed between the change of state of a Midi controller and the plugin/computer restart, there is a higher risk that the external controller has a different state.

Save Interval defines the interval between disk saves. The file may be large, and real-time updates aren't really necessary. The default value of 60 seconds means that when the plugin shuts down, midi commands issued in the last minute (max) may not have been saved to disk. Disk saves are only performed if there has been a Midi activity since the last save.

Max age defines the maximum age of Midi commands to restore when the plugin starts. The default value of 24 hours means that commands made more than a day ago will not be restored. The idea is that commands issued long ago may not be relevant when the plugin starts and are hence not restored.