Siemens SIMATIC S7-300 Series Reference Manual page 93

Can I use DPV1 Slaves without this migration?
Yes, without restriction. In this case, DPV1 Slaves behave as conventional Slaves.
SIEMENS DPV1 Slaves can also be operated in S7 compatible mode. For DPV1
Slaves of other manufacturers you require a GSD file to EN50170 below Revision
3. DPV1 – station-wide.
You must convert the complete station to DPV1 mode if you migrate to DPV1. In
STEP 7 you can configure this mode in the HW Config module (DP Mode).
Details on migration to DPV1 mode are found in our Customer Support
under FAQ topic ID: 7027576
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
A5E00111190-01
CPU 31x-2 as DP Master/DP Slave and Direct Communication
2-3