The interrogation reports provide instances of AP and SAP being among the ammunition carried for 105mm guns on type IXs, as well as HE, incendiary and AA-HE. No starshell mentions seen so far.
The AA-HE could be used against ships as well as aircraft.
Also, from another
site, U-701, a type VIIC, employed SAP, HE and incendiary to sink the USCG cutter
YP-389