Most Room 234 code online is Room 2.x (androidx.room). Room 3.0 (stable 1 July 2026, 3.0.3 on 9 September) is a Kotlin Multiplatform 25,990 rewrite under a new group and package, androidx.room3, so it can live beside Room 2.x, which WorkManager 234 (WorkManager) still uses internally. Room 2.x entered maintenance mode in March 2026, with bug-fix releases (2.8.5 is current) but no new features. BookNest uses Room 3.0.3.
| Room 2.x (androidx.room) | Room 3.0 (androidx.room3) | |
|---|---|---|
| Code generation | Java or Kotlin; KAPT, Java AP or KSP | Kotlin only, KSP only |
| Database access | SupportSQLiteDatabase, Cursor | SQLiteDriver and SQLiteConnection |
| Blocking DAO functions | Allowed off the main thread | Not allowed: suspend or Flow |
| LiveData, RxJava, Paging | Built in | Separate artifacts, registered converters |
| Platforms | Android, JVM, iOS (2.7+) | Android, JVM, iOS, JS and Wasm |
Porting from Room 2.x is mostly mechanical: change the imports, make every DAO function suspend or reactive, call setDriver(), rename the converter annotations, and rewrite migrate() bodies for SQLiteConnection. On the web targets, androidx.sqlite:sqlite-web keeps the database in the browser's Origin Private File System. Start new apps on Room 3.0, and move older ones when you next touch the data layer.