Files
TrinityCore/sql/TBC-WLK_converter

Convert DB from 2.4.3 to 3.0.x:

1. BACKUP your old db!
2. Run TBC-WLK_characters.sql in "characters" database.
3. Run TBC-WLK_world_run_only_once.sql in "world" database.
4. Run TBC-WLK_world.sql in "world" database.

After that you need to manually apply all sqls starting from 805_world_scripts.sql (in sql/updates)
!IMPORTANT! If your professions' tools aren't detected in inventory after upgrade to 3.0.x, please delete your "Cache" directory in client's one.
Ask your testers to do so no matter what, too. !IMPORTANT!