Does Shmitat Kesaffim apply to loans made with a heter iska (and no prozbul) or are those loans halachically deemed to be investments and not loans so it wouldnt apply?

Loans made with a Heter Iska, are officially considered a "half loan and half security deposit". Accordingly, without a Prozbul, Shmitat Ksafim annuls the loan half, and one cannot collect it. Accordingly, all Jews who have used the Heter Iska, should do a Prozbul as we approach this coming Shmitta year, and for sure in Israel, for bank accounts in all Israeli banks, are done based upon the Heter Iska.