With the startup state setting you can control the state of your luminaire when it is turned on. As a default the startup state is set to 'Default' mode and that means that the luminaire will go to default mode after it has been turned on.
With the 'Last state' mode the luminaire will remember the state it was in when the luminaire was turned off and it will go to the same state when turned on again. You can also set a minimum level for the Last state. This means that if the luminaire was at 0% when turned off it would still go to some minimum level after it is turned on again.
You can find the 'Startup State' setting under Luminaire settings. Double tap on a unit under the 'Luminaires' tab in Casambi app, and scroll down to find the "Startup state for power ON" row.
Alternatively you can set this mode for all the luminaires in your network by navigating to: 'More' -> 'Network setup' -> 'Configure all lumianires' -> "Startup -> LAST STATE or DEFAULT MODE"
Luminaire properties after double-tapping on the unit: