My control centre will not open. What to do? Who is the "developer"?

Apple provides the system and all 3rd party developer's are responsible for providing software that is compatible with the system. When Apple released Catalina the developers were given nearly a year to update their software. However, many didn't and those include a lot of printer manufacturers.

You don't give the name and model of your scanner but for most all scanners the 3rd party application of VueScan works like a charm. You can use it in demo mode before purchasing. I use it with my two scanners and it's better than the software that came with the scanners.

Have you tried Image Capture and/or Preview to scan with your scanner?

Brother's ControlCenter2 product is not supported on macOS Big Sur. Check with the Brother site for the correct software and driver support for your anonymous device on Big Sur.

The answer given was about a Brother printer. But I believe the question was about Apple Control Center - the one that came with the MacBook and has all the settings for printers and keypads, etc.

I can't open mine either. It tells me the app needs to be updated and when I went to "more information," I was taken to an Apple screen that discussed the transition from 32 bit to 64 bit. Does this mean Apple is not updating its own software? Really confused. Any help would be greatly appreciated.