Hello Rajan,
Currently there is 1503 version available for S/4 HANA Finance certification.
You can check about it here:-
The new course of 1511 and subsequent certification would take 6-7 months (my guess) just like how 1503 certification of S/4H Finance came.
In case you want to appear for one, my suggestion would be to go for the 1503 version.
Regards
Rishab