Well it worked. Thanks to everyone for your help!
For the record, here's what I had to do:
I had the problem that when I was in the dev channel and changed it to stable, if I restarted the tablet, or even simply backed out of that screen where you select the channel, the tablet would not "keep" the stable channel as my setting, but would instead revert it back to dev on its own. So, what worked for me, was I had to select the stable channel, and then on the side change from the update setting to the about setting, and there tap on "check for updates". That seemed to cause the OTA-7 upgrade to occur. The tablet restarted, and I am now on OTA-7 on the stable channel. I also selected the option to reinstall all applications, and updated all applications that needed updating.
One remaining question I have: In the future, when there are updates to the OS - major updates or minor - will my tablet now simply just accept the OTA updates that are sent to it (provided that I allow that)?
P.S.: How does a person "close" an issue on this forum?