What is the implication on queries that used to run against wb_terms during migration?

Property terms are a tiny fraction of the whole terms store, so we will migrate and switch them to new store much earlier than items. This might require tools to query property terms from the new store, while keep querying item terms from the old store for the time when we are still migrating item terms.

We will announce the dates for when the tools have to switch to reading from the new store, for property terms and for item terms separately, at least 6 weeks before we do the switch in production to give tool builders enough time to update and test their tools.