TD-W8970 vs TD-W8970B: Difference in hardware or just software/firmware?

Hi *,
I am currently using a TD-W8970 v1 as a modem for my VDSL50 connection over annex B. My internet provider will switch over to ALL-IP based on Annex J in the next 2 weeks. Therefore, I am asking myself wether I have to use a TD-W8970B v1, because only this router supports Annex J according to the TP-Link specs. Or, do I just have to use a compatible firmware from xdarklight if the ony coming with LEDE doesn't work.

There are differences in the hardware. But these difference are only relevant for ADSL connections. VDSL uses the same frequencies at least across Europe and there is no Annex A/B (in terms of frequency spectrum for VDSL).