https://userapps.support.sap.com/sap/support/knowledge/en/3744653
3744653 - Legacy custom business objects not visible in new Custom Business Objects app (F1712A) -...
Custom business objects created in the older Custom Business Objects app (F1712) do not appear in the new Custom Business Objects app (F1712A).
custom businessnot visiblenew applegacyobjects