How to install APK and XAPK files on Android

Most downloads on APK Rewind come in one of two containers. An APK is a single package that Android installs directly. An XAPK is a zip archive that bundles the base APK with its split APKs (per-language, per-screen-density and per-CPU parts) and, for large games, an OBB data folder. Android's built-in installer does not understand XAPK, so it needs one extra step. Both formats contain the same app builds developers publish to Google Play; nothing is repackaged or modified.

Installing an APK

Download the APK from the version page and open it from your browser's download list or a file manager.
The first time, Android asks you to allow installs from that source. Tap Settings, turn on Allow from this source, then go back.
Tap Install. If the app is already installed from Google Play, you can only install a newer or equal version signed by the same developer; downgrading requires uninstalling first.

Installing an XAPK

You need an app that can unpack the bundle and install its parts together. Any of these works:

APKPure app - opens XAPK files directly; it is also the mirror most downloads here come from.
SAI (Split APKs Installer) - open source, available on Google Play and F-Droid, installs XAPK/APKS/APKM bundles.
Any file manager with XAPK support, for example ZArchiver plus a manual install of the extracted APKs.

Install one of the installers above from Google Play.
Download the XAPK from the version page.
Open the installer, choose the downloaded XAPK (or tap the file and pick the installer when asked).
Allow installs from that source when prompted, then confirm. For games with OBB data the installer also copies the data folder to Android/obb, which may take a minute.

Manual method (no installer app)

Rename the file from .xapk to .zip and extract it.
If the archive contains only one .apk, install it like a normal APK.
If it contains several APKs (base plus splits), they must be installed together, which the stock installer cannot do - use SAI, or on a computer run adb install-multiple base.apk split_*.apk.
Move any Android/obb/<package name> folder from the archive into the same path on your device's storage.

Common errors

App not installed - usually a signature mismatch (an older version from a different source is already installed) or not enough storage. Uninstall the existing copy, or free space, and retry.
Parse error - the file is incomplete or your Android version is below the app's minimum. Re-download, or pick an older version whose Requires Android field fits your device.
Blocked by Play Protect - Play Protect warns about apps installed outside the store. Tap More details and Install anyway only if you trust the source; the files here are served by an established mirror.
Game starts then closes - the OBB data folder is missing or in the wrong place; reinstall with an XAPK installer, which places it correctly.

Which version should I choose?

The latest version is the safest choice. Older releases are useful when a device is below the current minimum Android version, when a newer build removed a feature, or when a game update broke a save. Note that server-backed apps may stop working on very old builds once the developer changes their servers; each version page shows its release date and requirements.