Short answer: in either app, go to More → Settings → Data and backup → Create backup, tick everything, and save the .tachibk file somewhere off the phone. Restore it from the same menu in Mihon. Act while Mihon is on 0.21.x: it is the last major version line that restores .tachibk directly.
What a .tachibk backup contains
- Your library: titles, categories and reading status.
- Chapter progress: read/unread flags and reading history.
- Tracking connections (you may need to log in to a tracker again after restoring).
- Source and app settings included in the backup options.
- Not the downloaded chapter image files themselves — those live in the app’s storage folder. A backup restores the records; chapters marked downloaded are re-fetched or re-linked from storage.
Create a backup
- Open Tachiyomi or Mihon → More → Settings → Data and backup.
- Tap Create backup and tick all categories: library, chapters, categories, trackers, history, settings.
- Choose a save location you control. The Mihon team’s own upgrade advice is blunt: “Ensure you have a up to date backup before updating to this version.”
- Copy the file off the device — a backup that only exists on the phone it protects is not a backup.
Where to keep the file
The file is small, so keep two copies: one on a computer and one in cloud storage. Our cloud backup guide compares pCloud, Backblaze and a free manual Google Drive routine for exactly this job. Whatever you choose, rename copies with the date (for example library-2026-10.tachibk) so you always know which is newest.
Restore a backup
- Install Mihon first and add your extension repositories plus the extensions you used (repository guide) — restoring before this step leaves entries unlinked.
- Go to More → Settings → Data and backup → Restore backup and pick the file.
- Wait for completion, then check the library, categories and a few titles’ progress.
- Re-login to trackers if prompted (tracking setup).
The deadline you should know about
Mihon’s release notes for 0.21.0–0.21.2 state that this is the last major version line supporting Tachiyomi’s backup format and extensions made for it. After the next major version, the only route for a .tachibk file is to restore it on 0.21.x first and then update. A backup created today stays useful — but restoring gets one step longer. Full walkthrough: migrate from Tachiyomi to Mihon.
Restore problems
A “decryption failed” message has specific causes and fixes — see decryption failed, explained. If the app hangs while updating its database after a restore or upgrade, see stuck on the updating screen. Never delete the old app or its data until the new install has restored successfully and you have opened a few chapters.
Related: all tutorials · organize your library