Thank you for contacting us. The good news is, neither mSecure 3.5.7 or 4.5.4 actually make use of an email address to run them. Those versions were not connected to any centralized account system as mSecure 6 is. In order to upgrade, you will need to do so on your phone to make sure any custom icons and attachments get imported.
To upgrade, simply download mSecure 6 from the App Store app on your iPhone, then open the app and create a new account (because with the older versions, there is no mSecure account). When you go through the app setup, you should get the option to import data in from mSecure 4. Tap the button to import, enter your mSecure 4 password, and you should be good to go. After the app is set up on your iPhone, simply download mSecure 6 on your desktop computer, open it, and sign in to the account you just created.
I have two versions of msecure with the same email address. I have all Apple devices.
Version 3.5.7 is currently on my desktop.
Version 4.5.4 is on my phone.
Each of these versions use my email address but different passwords.
How do I upgrade?
When trying to load the Version 6, I get a message that I have an account by the same password but will not let me log in because I have only a 4-number password.