Devices "Unavailable" after upgrading to 2020.12.1 from 0.103

My devices are all “unavailable” after upgrading from 0.103.x to 2020.12.1.
I could use some input and guidance on how to get them back.
I have mostly Phillips Hue lights.

0.103 was released around a year ago, there were so many changes and breaking changes in this time that in my opinion it doesn’t make sense to try to fix it and instead start from scratch.
The other option would be to read all the changes (around 10-15 releases) and fix everything, but I don’t recommend this path.

Look into breaking changes.

Recheck integration for non working items. You may need to setup again.

103 to 2020.12.1 is big jump and several things have changed.

Are you using the Hue hub or zigbee usb stick?

Also, what host? Rpi3,4, etc

I’m running a RPi4 and I’m using the Hue Hub.
I rebooted and found fewer “unavailable” devices, but they still don’t work.
I added my Rachio sprinkler and it looks like it will work, but being winter I don’t want to actually run anything there.
I’m willing to reconfigure all the “unavailable” devices. Not sure how to do this however, so could use some help there. I’m using the Lovelace interface configuration add on I think… at least that is what I used to add the Rachio sprinkler…
Or will I need to connect directly to the RPi with a keyboard, mouse and monitor?

Sorry, this is probably pretty basic stuff, just after a year from when I set up the original system I forgot how I originally set things up. Actually I had some trouble back then and kind of gave up till now. I’m revisiting HA after reading that many more things can now be done directly from the Lovelace UI.

I rebooted (I’m not sure what it was) from the UI and now all the devices I had before appear to be working (i.e. they are not grayed and no “unavailable” tags).
I rebooted before as well from a different location (the Supervisor). This is about the 3rd time I rebooted I think.
I’m a bit unclear how many things there are that can be rebooted. I see the RPi app is now called the Host system (according to the UI at “Supervisor” and the “System” tab, and it is running version Home Assistant OS 5.8. And then there is the Supervisor which is Version 2020.12.1. Where is this running? I thought 2020.12.1 was what was running on the RPi.
Is there somewhere that explains all of this?

In any case the original problem has been resolved.

Now on to figuring out how to update the Phillips Hue Integration with bulbs I added since I installed the original bulbs last year.

Wow! All our Hue lights were under “Lights” in the Lovelace UI. I copied the system managed dashboard and edited the new copy to arrange the Hue lights into rooms. It is looking pretty good.