Yes, Honor 9N supports VoLTE in both the SIM slots since VoLTE works on bands 3,5 and 40 and both the SIM slots in Honor Play Pro supports band 3 and 40. You can use two Jio SIMs at a time in Honor 9N.
Specs: Honor 9N
Sri Ram Nair
Honor 9N comes with a battery of 3000mAh non-removable battery. The battery is sufficient to last for a day for your normal daily use.
You can check here for specs: Honor 9N
Yes, Honor 9N supports 4G VoLTE. VoLTE or Voice over Long-Term-Evolution is the latest technology in India for high-speed internet and communication. It works on band 3, 5 and 40. Since the Honor 9N supports Band 3 and 40 in both the sims,so it supports VoLTE along with 4G in both sims.
You can find the complete set of specifications of Honor 9N here: Honor 9N
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