Four By 21 v7.0
APK · 11.3 MB · version code 44 · Android 8.0+ · uploaded Aug 29, 2025
- Signature matches the Google Play version Details
Quick check before downloading
Answer this to unlock the download. It keeps automated downloaders away.
File information
- Version
- v7.0 (44)
- Uploaded
- Aug 29, 2025
- Size
- 11.3 MB
- Requires
- Android 8.0+ (API 26)
- CPU support
- Any (no native code)
- Screen
- Normal screens and larger
- MD5
- a85ae8c5c2e7a486b667b2d498f07ee0
- Signing certificate (SHA-1)
- 89:CD:18:1F:BD:48:F5:4E:96:2B:ED:35:48:47:B9:F0:21:21:A5:BF
- Signed by
- CN=Alexander Harm, L=Medford, ST=MA, C=US
- File name
- net-aharm-fourby21-44-71547657-a85ae8c5c2e7a486b667b2d498f07ee0.apk
- Package
- net.aharm.fourby21
- Downloads (all versions)
- 50K+
- Age rating
- PEGI 3 · Everyone
Permissions (9)
This version requests 9 permissions, none of them sensitive.
- Access adservices ad id android.permission.ACCESS_ADSERVICES_AD_ID
- Access adservices attribution android.permission.ACCESS_ADSERVICES_ATTRIBUTION
- Access adservices topics android.permission.ACCESS_ADSERVICES_TOPICS
- Advertising ID com.google.android.gms.permission.AD_ID
- Full network access android.permission.INTERNET
- Internal broadcast protection (app-defined) net.aharm.fourby21.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
- Prevent the device from sleeping android.permission.WAKE_LOCK
- Run foreground services android.permission.FOREGROUND_SERVICE
- View network connections android.permission.ACCESS_NETWORK_STATE
Security & authenticity
Security rating: Trusted
Signing certificate
- Signature matches the Google Play version Checked by the source store on Aug 29, 2025.
- Certificate issued to “Alexander Harm” This is the certificate of the Google Play version.
Store checks
- Developer signature verified Aug 29, 2025
- Validated against Google Play Aug 29, 2025
- Uploaded by “appupdater” Gold tier · 117,810 followers · uploading since 2020
Scans come from the source store; the certificate comparisons are AAPKs's own, made from the files' published signatures. AAPKs doesn't scan files itself.
How to install Four By 21 on Android 8.0+
You'll need about 22.5 MB of free space.
- Download the APK — tap Download APK above (11.3 MB). Chrome shows “File might be harmful” for every APK file; choose Download anyway only if you trust this file.
- Open the file — tap the download notification, or open Files › Downloads and tap net-aharm-fourby21-44-71547657-a85ae8c5c2e7a486b667b2d498f07ee0.apk.
- Allow the install (first time only) — Android 8 and later asks for permission the first time an app opens an APK: tap Settings in the prompt, turn on Allow from this source, then go back. Manual path: Settings › Apps › Special app access › Install unknown apps (on Samsung: Settings › Apps › ⋮ › Special access). On Android 7 and older: Settings › Security › Unknown sources.
- Check the file (optional) — the MD5 of the downloaded file should be a85ae8c5c2e7a486b667b2d498f07ee0. If it differs, the file is damaged or was changed: delete it and download again.
- Tap Install — Android asks “Do you want to install this app?”. If Google Play Protect shows a warning, read it before you continue: the source store rated this file Trusted, but only install apps from sources you trust. If an earlier version is installed, this one only installs as an update when it is signed with the same certificate (SHA-1 shown above).
- Open Four By 21 — tap Open on the install screen, or find it in your app drawer.
Common install problems
- “App not installed” — a version signed with a different certificate, or a newer version, is already installed (Android doesn't allow downgrades). Uninstall it first; back up your data, because uninstalling deletes it.
- “There was a problem parsing the package” — the file is incomplete, or your Android is too old (this version needs Android 8.0+). Download it again, or pick an older version.
- Blocked by Play Protect — Play Protect checks apps from outside the Play Store. Only continue if you trust the source.