HMD Global is rolling out a new server-side update to the Nokia 7 Plus fixing the network related bugs. Post the June 2018 security update on the Nokia 7 Plus, several users stated that they're facing issues related to dual VoLTE. However, the company has now fixed the VoLTE issues faced by the users on the Nokia 7 Plus with a server-side update. HMD has already issued the update, so there's nothing you should do at the moment. If you want to check whether the update reached your device or not, you can make a VoLTE call by using Jio network or any other VoLTE supported network.
Juho Sarvikas, Chief Product Officer at HMD Global, confirmed this news on Twitter stating the Modem config file was not loading properly in the previous update, which has now been fixed. Being a modem config file fix, HMD fixed it instantly and did not wait to include it in the July security update.
Back in May 2018, HMD Global released a major OTA update to the Nokia 7 Plus, which added support for Vodafone VoLTE, Dual 4G & VoLTE functionality along with some other features. Earlier, it was working fine, but the June 2018 update broke the Modem config file as the CPO of HMD highlighted. It was a major issue as Jio users were not able to make or receive voice calls from the smartphone.
The Nokia 7 Plus in India supports VoLTE on Reliance Jio, Bharti Airtel and Vodafone India. Jio has pan-India VoLTE coverage, while Airtel and Vodafone's VoLTE service availability is limited at the moment. If you're from any of the eligible regions, you can try out the VoLTE on Airtel and Vodafone networks too. Idea Cellular is yet to release VoLTE support for Nokia 7 Plus, which might happen with the July update.
HMD Global launched the Nokia 7 Plus in April 2018 for Rs 25,999. It's one of the best mid-range smartphones available on the market right now. The 7 Plus is also part of Android P Beta program, and the company even rolled out second Android P Beta update for the handset recently.