hi Holger Niehaus,
my plan is to still support the method enableFullTextFilter as I think it's very convenient to declared "filters" (conceptually) in this way.

The @FullTextFilterDefs will have to change slightly of course, as for example your @Factory annotated method would need to return something different.

I don't have a POC for this yet so details will likely change, but the gist is that we intend to still provide the filters feature to Hibernate Search users, as you suggest likely by using BooleanClause.Occur.FILTER and hopefully to be able to still cache pre-computed bitsets when underlying index segments didn't change.

Ideas welcome! However if you're just moving to 5, no worries we'll not remove this until at least 6.