They say it will only be 5-10 minutes.. So we can probably assume this will be around 3-4 hours
I assume my server will automatically reboot afterwards.. In case it doesn't, I may have to manually restarted, which if this happens in the middle of the night, I probably won't get to doing it until the morning..
It is also possible nobody will even notice the reboot... But I'm just giving everyone a heads up that if my whole site and forum goes off-line, then people know why...