Is VoLTE dependent only on the Firmware your handset is running or also on the 4G Bands your phone has?
Is there a way to find out which '4G/LTE Band' is necessary for VoLTE to work for a particular Operator?
My Operator: Boost Mobile, uses 4G Bands: 3, 7, 28 (as informed by Boost Technical Support over call)
Telstra uses 4G Bands: 1, 3, 7, 8, 28
My Phone: Redmi Note 5 Pro, has Bands: 1, 3, 5, 40, 41
I don't get VoLTE on my handset and the network falls back to 3G when I'm on a call. This sometimes makes it difficult while using the phone as a Hotspot. I'm thinking of buying a new phone, probably Redmi Note 9 Pro which has Bands: 1, 3, 5, 8, 40, 41.
Would VoLTE work on this handset? There are peeps who have reported that VoLTE works on their "Mi" phones, so I think it is not entirely dependent on Firmware (obviously, Xiaomi's Firmware wouldnt be certified by Telstra/Boost)