Thank you for contacting us and I'm sorry about the issue you are experiencing. You can learn how to download the previous versions of mSecure here: https://m7software.freshdesk.com/support/solutions/articles/36000022187-download-the-previous-versions
mSecure 4.5.4 is the app for iOS or iPhone/iPad. That is not available for Android. Android has mSecure 4.0.6. Either way, the app is no longer for sale so it will not show up in a regular store app search. However, as the article above demonstrates, you can still always re-download purchased apps. We do not provide APK files for any version of mSecure.