HF we have - 2 with SELCAL.
I found that the Indonesian UJUNG PANDANG FIR (which is east of WIHH and thus not on the flight path...) has ADS-C and CPDLC, but I haven't seen anything saying its mandatory. Singapore would require it, but weŽll pass them by.
CPDLC and ADS are operational in the VOMF / Chennai FIR, still I canŽt find info if it is mandatory...EDIT: its not, just found the Indian AIP online:
The procedures described below are applicable to aircraft utilizing ADS/CPDLC services within Chennai,Mumbai and Kolkata FIR. The use of data link services will not affect current procedures for nondata link equipped aircraft operating in the same airspace.