Migration

Migration

Hayai's J2K reset keeps the J2K database as the source of truth for manga, chapters, categories, history, tracking, downloads, and image-reader state. Hayai stores only data J2K cannot represent, such as novel metadata, quotes, statistics, and E-Hentai state.

Before migrating

1. Create an in-app backup from your existing installation.
2. Copy the backup and any important downloaded files to a safe location.
3. Keep the old installation until you have checked the migrated library.

Legacy database import

The importer may read a legacy tachiyomi.db, but it never writes to it. The active database is hayai-j2k.db; the files have unrelated migration histories and must not be swapped or renamed.

Import is intentionally conservative:

• Core records are imported in dependency order.
• Every legacy source row is preserved for recovery and auditing.
• A durable marker makes completed imports idempotent.
• Identity conflicts stop the migration instead of guessing or silently dropping data.

If migration reports a conflict, preserve both files and the backup. Retry from Settings > Advanced only after resolving the reported condition. Do not edit either database manually unless you understand the schema and have a second copy.

After migration, compare library counts, categories, reading progress, novel entries, quotes, and reader settings before removing the old installation.