Just looked at the mission brochure; the second stage will not use the HTVE-Vac engine (846.8 kilonewtons), but rather the Vikas 2B engine (803.78 kilonewtons).
The 32 hr countdown activity has commenced at 20:04hr IST on Tuesday, April 10, 2018 for the launch of PSLV-C41/IRNSS-1I Mission scheduled at 04:04 hr IST on April 12, 2018
On addition of any new safety mechanism in IRNSS-1I to avoid power failure, the chairman said, “Power systems used in GSAT-6A and IRNSS-1I are totally different. The power system being used in IRNSS-1I is very simple and proven as all seven navigation satellites launched earlier are working successfully.”