Downloading APKs from third-party sites is always risky. Since the official 2015 version is no longer distributed by Keepsafe, any APK you find could have been:
If you have an older Android device (pre-6.0) that cannot run modern apps, consider using a basic file manager with a ZIP password feature or upgrading to a newer phone. Your private photos and documents deserve active protection, not a relic from 2015. Keepsafe Apk 2015
: Never move your only copy of a photo into an old vault. Keep a backup on a PC or physical drive. Downloading APKs from third-party sites is always risky
This vulnerability allows attackers to modify an APK without breaking its signature. If your 2015 APK was tampered with before you downloaded it, a hacker could replace the encryption code. : Never move your only copy of a photo into an old vault