Moving soon to Mac Mini 2018 with Catalina requiring 64 bit apps. This 64bit checker, Go64, reports: ''Thunderbird.app is a 64-bit app with some internal components that are still 32-bit. It may or may not run correctly on macOS 10.15, depending on how the app handles situations where its 32-bit components would normally be used. Check for a more recent version or contact the application's developer for more information. When reporting an issue, please include this information: BundleID: org.mozilla.thunderbird Version: 68.11.0 These components are 32-bit: /Contents/MacOS/libxpcom_core.dylib'' Think this will be a problem? I see TB 78 is out but you can't upgrade from TB 68 (I have many, many emails and multiple accounts). Thanks