1Password tells me to update, then won't update

Several times a day, I get a 1Password notification on my Mac, that I should install an update. I click install, and then nothing else happens, until the notification appears again, some hours later. If I go to the 1Password menu and choose Check for updates, it gives no indication of checking or doing anything else. Absolutely nothing appears to happen.

I see that the latest version of 1Password requires macOS Catalina or later. This Mac is running MacOS Mojave, so maybe that is the problem. But for 1Password to prompt for permission to update, then do nothing, is a user interface failure, as is displaying nothing when I choose Check for updates from the 1Password menu. 1Password should display a message explaining the situation, and telling me whether or not an update is available. If there is no available update, 1Password should not tell me several times a day that there is an update available.

Is there a 1Password update available for version 7.8.5 on Mojave? Or am I at the end of the line, until the macOS is upgraded? If an update is available, how do I install it? If no update is available, how do I stop getting the 1Password update alert messages?

1Password Version: 7.8.5
Extension Version: Not Provided
OS Version: MacOS 10.14.6