If all goes well by the due date here, we should be confident that property terms can be now switch completely (reading and writing) to new schema. Wait couple of days after switching to MIGRATION_WRITE_NEW before doing this
|operations/mediawiki-config : master||Stop writing to wb_terms for properties in Test Wikidata|
|operations/mediawiki-config : master||labs: Set migration stage for properties to new|
Thinking again about this, we probably should not switch this to WRITE_NEW until we can switch tmpItemermsMigrationStage to WRITE_NEW as well.. just in case we have to switch back to WRITE_OLD or WRITE_BOTH temporarily to fix any issues we face while running item terms migration.