Section 4 of the Bharatiya Nagarik Suraksha Sanhita, 2023 (BNSS) deals with:

Section 4(1) of the BNSS provides that offences under the Bharatiya Nyaya Sanhita shall be investigated, inquired into, tried and otherwise dealt with under the Sanhita, and section 4(2) applies the same provisions to offences under any other law, subject to any enactment regulating the manner or place of dealing with them.

So the section covers "trial of offences under both the Bharatiya Nyaya Sanhita and any other law"; it does not refer to the repealed IPC.