| ⇢ | A | initial_backup_schema added | |
| A | ↛ | initial_back_schema removed |
| ⇢ | A | initial_backup_schema::update_schema() added | |
| ⇢ | A | initial_backup_schema::revert_schema() added | |
| A | ↛ | initial_back_schema::update_schema() removed | |
| A | ↛ | initial_back_schema::revert_schema() removed |