A Tachiyomi backup and its extensions need separate checks before you update beyond Mihon v0.21.2. The pinned release gives a route for restoring the backup, but that route does not establish whether your extensions will work after a further update.
The documented route is to restore a .tachibk backup on Mihon v0.21.2, then update to the latest version. The v0.21.2 release notes say subsequent versions will no longer restore that format and the next version will drop compatibility with Tachiyomi 1.4 extensions. This review covers those documented warnings; our sandbox did not test the migration.
The v0.21.2 release notes warn that duplicate entries and chapters left over from older versions are merged during the update and that this cannot be undone. This warning appears in the included v0.21.0 changes. Preserve a backup before updating rather than treating restoration as a substitute for protecting the original collection.
Mihon fits readers who supply their own content
Mihon hosts no content. Its README requires Android 8.0 or newer and lists local reading, configurable viewers and reading directions, categories, scheduled chapter checks and trackers including AniList and MyAnimeList. These are documented capabilities. Reading speed, battery use and Android stability were not measured in our run.
The getting-started guide describes opening the downloaded APK, then supplying local content or extensions. After installing an extension, readers can select its source, browse or search for a series, open its details and press "Add to library". These are documentation-based instructions, not steps executed in our sandbox. Before moving a collection, check whether your chosen sources have the titles you need. The guide suggests checking spelling, romanized Japanese titles and alternate names when searches fail.
What happened when we ran it
Our sandbox completed repository installation for commit deeb9b2 in 164 seconds on 2026-10-18. The build failed after 18 seconds and the test command failed after 23 seconds, both with exit code 1. These are the recorded command outcomes, not Android APK installation timings or reading benchmarks.
Our source build stopped at a missing Android SDK. The build log requests ANDROID_HOME or an sdk.dir entry in local.properties. Configuring a valid SDK location and repeating the build is the next diagnostic step; this error does not establish a defect in the reader. The test excerpt ends with a Gradle exception but omits its underlying cause. We cannot attribute that failure to SDK discovery or report a passing-test count.
The recorded configuration was 3 CPUs, 10 GB RAM and image label lab-jvm:21. That label does not establish actual runtime versions. The checkout contained 1,466 files, about 98,801 source lines and occupied 19.8 MB. Our scan found 3 CI workflow files, no Dockerfile and no tests directory. A directory scan alone cannot establish whether tests exist elsewhere in the project. APK installation, reading behavior, backup restoration and extension loading remain unassessed.
Check the restored library and extensions separately
Keep the original backup, follow the release's restore route and inspect the restored collection before updating further. Then check the extensions your essential sources require against the stated compatibility cutoff. This is a suggested verification sequence, not a migration procedure completed by our sandbox. Restoring library records does not demonstrate that an extension can load or retrieve chapters.
The v0.21.2 notes also report fixes for updates from v0.20.x failing on some older databases and for some previously downloaded chapters no longer appearing as downloaded. These are maintainer-reported fixes, not faults reproduced here. They provide reasons to read the release notes carefully, but they do not establish that a particular collection will migrate successfully.
Alternatives address different requirements
Komikku's README lists merging multiple library entries. Komikku is an Android reader fork based on TachiyomiSY and Mihon/Tachiyomi. Consider it when combining entries is a requirement for your library. The feature is documented; we did not test its behavior, reliability or ease of use.
Suwayomi Server's README says direct downloads include Suwayomi-WebUI. Suwayomi Server is a manga-reader server that runs extensions built for Mihon and supports browser access to a running server. It is worth considering when browser access justifies operating a service. Its README warns that actual feature support depends on the front end, so check your intended client and extensions separately.
For a Mihon migration, start with the backup format and essential extensions. Keep the original backup until you have checked the restored collection and the requirements of the version you intend to use.