Lantern Sudoku
Privacy Policy
Last updated: 11 October 2026 · applies to Lantern Sudoku 1.0 and 1.0.1 for Android, from Google Play, F-Droid and GitHub
1. Information we collect
None. Lantern Sudoku does not collect, send, sell or share any personal information. The app asks Android for no permissions at all, including internet access, so it cannot send anything over the network. There are no advertising, analytics or crash-reporting tools in the app.
2. What the app stores on your phone
To let you continue a puzzle and see your progress, the app keeps, in its private storage on your phone:
- your games in progress and finished games (the board, your notes, time, hints used and mistakes),
- your statistics and daily streak, which are worked out from those games,
- your settings (for example theme, larger digits and the mistake limit),
- a little bookkeeping: which first-game tips you have seen, the date you first opened the app and, in the Google Play version, when it last offered the rating dialog.
This data stays on your phone until you clear the app's storage or uninstall it.
3. Android backup and device transfer
If backup is turned on in your phone's settings, Android may copy the data above to your Google account, and may move it to a new phone when you set one up. This is handled by Android and Google under Google's privacy policy; Lantern Sudoku itself never uploads anything. You can turn backup off in your phone's settings.
4. Sharing
When you choose to share a daily result, the app gives a short text (the date, level, time, hints and mistakes, and a grid of coloured squares) to the app you pick. That app receives the text and handles it under its own privacy policy. Nothing is shared unless you tap Share.
Settings › Licence opens the app's source code page in your browser. The browser makes that connection, not Lantern Sudoku.
4a. Ratings (Google Play version only)
After you finish a puzzle, the Google Play version may occasionally show Google Play's own rating dialog (at most once every 60 days, and never on your first day). The dialog is shown and handled by the Google Play Store app under Google's privacy policy; Lantern Sudoku does not see whether or how you rate, and sends nothing itself. The F-Droid and GitHub versions never show it.
5. Crash and performance data
The app contains no crash or performance reporting. If you have allowed it in your phone's settings, Google Play may give developers aggregated, anonymous app stability statistics (for example crash rates). These never include your games.
6. Children
Lantern Sudoku does not collect any data from anyone, including children.
7. Feedback
If you email us, we receive only what you choose to send, and use it only to reply and to improve the app.
8. Changes
If anything changes, we will update this page and the date above before releasing the version that changes it.