Hi Niloo,
Thank you for contacting us. Since older versions of mSecure are no longer supported, the only version we can guarantee will be able to work after upgrading to the latest MacOS is the current version of mSecure 5 in the Mac App Store. I'm not sure if the message you received is saying the older version won't work, as it's just talking about optimization, but I haven't encountered that message myself, so I am not sure what will happen. Would you be willing to upgrade to mSecure 5? If so, you shouldn't have any problems installing the latest version of MacOS.
Niloo
hi... i am having an older version of msecure. as i was trying to upgrade the macOS, i got the warning that msecure is not optimized for my mac and may not open upon upgrading. i didn't move forward with the upgrade because i don't want to risk losing information. but at some point i will have to install the OS. can you please advise!