I don’t see dropAndCreateIndexes on MassIndexer presently – you were talking about that as a possible feature to add, correct?

Correct. I just created HSEARCH-3751 Open .

Until that's implemented (in Hibernate Search 6), I think the following procedure may work for you:

1. Drop indexes (indexing/searching will start failing, but from what I understood it's ok for your use case)
2. Set the lifecycle strategy to create (that's the default).
3. Upgrade one node to the latest version.
4. When it's up, you know the indexes were created: upgrade all other nodes to latest version.
5. Initiate a reindexing from one of the nodes.