How to fix common APK install errors on Android.
Each error below maps to a single decision step. The errors are listed in the order they typically appear in an install attempt.
Install failed: version downgrade (INSTALL_FAILED_VERSION_DOWNGRADE)
The new APK has a lower versionCode than the installed app. Uninstall the installed app first, then re-install the new APK. Local data will be lost; back it up first if needed.
Install failed: insufficient storage (INSTALL_FAILED_INSUFFICIENT_STORAGE)
The device does not have enough free space for the new install. Free up space by removing unused apps or media, then retry.
Install failed: parse error or version downgrade
A parse error usually means the file is not a valid APK. Confirm the download size against the developer entry and re-download if needed. If the size matches, the file may have been corrupted in transit; clear the browser’s download cache and retry.
Install failed: update incompatible (INSTALL_FAILED_UPDATE_INCOMPATIBLE)
The new APK has a different signing key than the installed app. Uninstall the installed app and re-install the new APK. Local data will be lost.
Install failed: no certificates (INSTALL_PARSE_FAILED_NO_CERTIFICATES)
The APK is not signed. A valid Android APK must carry at least one signature. Re-download from the developer’s official source.
Install failed: older SDK (INSTALL_FAILED_OLDER_SDK)
The APK targets a newer Android version than your device runs. Check the minimum Android version on the developer entry and confirm your device.
Install failed: user restricted (INSTALL_FAILED_USER_RESTRICTED)
The device administrator has restricted sideloading. Either remove the restriction (Settings → Security → Device admin apps) or install through an allowed channel.
Still stuck
Use the contact section with the exact error code and the device model. The Yono Rummy library does not run a support desk but can usually tell you whether the error is environment-related.
When the installer says version downgrade
This is the INSTALL_FAILED_VERSION_DOWNGRADE path. The APK you are about to install has a lower versionCode than the app already on the device. Uninstall the existing app first, then re-install. Local data is not preserved across the uninstall, so export with Android backup first if you need to keep it.
When the installer says insufficient storage
This is the INSTALL_FAILED_INSUFFICIENT_STORAGE path. The error dialog names the shortfall in megabytes, and the Yono Rummy library’s own file sizes give a useful reference range: Yono Crash Rocket v1.1.0 sits at 30 MB while Yono Poker Texas v3.3.1 sits at 60 MB, so a single install needs roughly that much headroom plus space for the cache. Free at least three times the shortfall, then clear app cache from Settings → Storage before retrying.
Parse errors and unknown sources
A parse error means the file is not a valid APK. Re-download and re-verify. The "Install unknown apps" prompt not appearing means the file manager does not have the permission: open Settings, apps, the file manager, then Install unknown apps and toggle it on.