While this depends on the specific custom ROM developer, Android 7.x introduced a new partitioning system. If the ROM supports it, the tablet can download updates in the background and install them on a reboot, minimizing downtime.
: Proceed only if you are comfortable with recovery flashing and understand that this is a community-supported solution, not an official Samsung update. Download Samsung Tab 2 10.1 Gt-p5100 Android 7.1.2