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Bootstrap and jQuery are updated by WordPress and not the plugins. You see that when using our plugin since we use it
If you update your WordPress version you shouldn’t see this warning anymore.
The same thing happened to me having updated WordPress to version 5.6.2.
But after updating BackupGuard (Before logging out) and I pressed Ctrl + F5 to do a forced cache purge for that page. BackupGuard started working fine with no problems.