App developers eventually drop support for older OS versions to focus on newer APIs. Consequently, the latest version of an app might not even install on an older phone. The is often the only way for users with legacy devices to maintain app security.
"I updated to Lockit v5 and lost the 'Quick Copy' TOTP feature. I spent three hours rolling back to v3.2.1. Never updating again." – u/cyberpanda lockit old version
This update blended heritage with modern lines, maintaining the structured body but often incorporating a longer clochette and more robust handles. App developers eventually drop support for older OS
If you have already upgraded to Lockit v5.x and created a vault, you open it in v2.8.4. The encryption schema changed from PBKDF2-HMAC-SHA256 to Argon2id in v4.1. A downgrade will simply show "Corrupted File" errors. "I updated to Lockit v5 and lost the
Lockit v3.2.1 is vulnerable to the "Janus vulnerability" on Android (CVE-2017-13156). While unlikely to affect a normal user, if you are a journalist or activist, an old version is a hard pass.