The support for the legacy commerce search facets had been removed from the Studio client and backend. The facet editor for product lists does only support the multi-facet selection from now on.

Old documents that still contain the legacy single-facet format must be migrated manually. When migrating from CMCC10 you can use the migrate button in CMCC10 2104+ to migrate your legacy values before migrating to CMCC11. If you still have legacy single facet values stored, a validator message is shown which gives the user a hint which value to select again.

(CMS-19295)