@Philbert I'll give that a try.

The directions said I should do an intermediate update (which it did) and then update to the latest firmware. When it started up and I saw all the stuff going on (or, in this case, not going on) I figured I had better ask before trying to do another update.

Guess this will have to wait until Monday!

Thanks.

@Philbert The saga continues. I managed to upgrade the controller. Then I figured all would be well. No matter what I tried, nothing changed. The mesh works, clients are online, but I cannot adopt the APs.

Then I ran the Omada discovery utlility. It found the APs. There is one that needs to be adopted first--the one that is wired. I tried to adopt it. Wanted a username and password. Yes, I had that written down. Great!  Now I'm in business. NOT

I rebooted the controller.

I did manage to adopt the wired AP, its status changed to "provisioning" but next to the Mac address I get the note that the devide is not compatible with the current controller. After a time, the AP shows up as connected. Now what? Before I did the last controller update, I could see all the APs. Now I only see the one that I managed to adopt. But since it says it's not compatible with the controller, I can't seem to do anything with it.

So--can't upgrade the controller because it won't talk to the old APs. Can't upgrade the APs because they won't talk to the controller.

What will happen if I do a factory reset? Will it revert to the old firmware? Will the entire network go away?

@Byteguy 

If this was me I would be thinking that either  

1.  The APs are adopted on the older controller

2.  The Firmwares are on the older / wrong channel

I would be looking to reset the AP to factory defaults, then connect to it via the web interface using the address DHCP gives it (192.168.1.123 for example).  Once in there look to updating the firmware with the latest for the SDN 5.x channel (firmware 5.0.4 if memory serves).  Then try re-adopting, you may need to reset it again to clear any change you made by manually logging into it.

If you factory reset the controller it will stay on the current version, just removes all settings.   I would do an AP as a test first mate.. what firmware are you running on teh APs?

@Philbert Nope--advanced features are not enabled.

@Philbert All is well now. Finally found the link where I could upgrade the root AP. Once that was done, I had access to the others and could upgrade them. Supposedly it would do all the upgrades at one at a time without me having to do anything, but that didn't work. Had to visit every one.

Once I get all that straightened out, I'll try to restore the configuration from one of the two files I exported. If that doesn't work, I guess I'll just have to go in and re-configure everything.

Sigh!

Well, I am a much happier camper this afternoon. Thanks for your help.

I really should document my trials and tribulations so others can benefit from this exercise.