Thank you for contacting us and I'm sorry about the issue you are experiencing. There is no mSecure 6. The latest version of mSecure is mSecure 5. We do no provide APK files. You can learn how to download the previous versions here: https://support.msecure.com/support/solutions/articles/36000064249-how-to-download-previous-versions
I am and was a happy (paid up) user of msecure 4. I see no compelling reason to move to v6
I just bought a new Samsung Note9 and the automatic SmartSwitch failed to install/copy a number of apps, including msecure 4.0.6
That would not be so bad if I could still install that from the Google Play Store, but it is not there anymore (only version 5.5)
Where can I get the APK for the latest v4 msecure so I can get back to where I was?