The encyclopedia and catalog structures have been updated to remove use of some types that were going out of support. There is currently no statement as to when this will happen or what the impact will be but the replacement types are supposed to improve performance. New encyclopedias will be created with the new structure.
Existing encyclopedias can continue to be used without being modified. They can be updated using SAEM but note that the upgrade time can be lengthy and unfortunately while we can provide a progress indicator there is no way to estimate timescale other than to warn when an excessive number of item records are found.
The menu option for this is Tool > Convert ntext and image types. Catalogs will be upgraded by Catalog Manager as usual.