Update:

HMD CPO Juho has announced in his recent tweet that the VoLTE issue faced by many Nokia 7 Plus owners post the June update has been fixed already.

It also seems that the fix is enabled from server-side and doesn’t need any user intervention.

Original:

While Nokia 7 Plus June security update brought Vodafone VoLTE support in India but it also gave headache to many Nokia 7 Plus owners. Not only it corrupted Nokia 7 Plus update to Android P Dev Preview but some users from India also reported issues with Dual-VoLTE support. Some even faced issues with Jio VoLTE, one of the popular Indian network providers.

HMD was slow to react to these issues sending many Nokia 7 Plus owners fuming. But seems they are already working to fix these issues as confirmed by HMD CPO Juho on Twitter. Juho has sought to assuage the owners  by saying that HMD is doubling down on these issues reported by users from India.

Though it still needs to be seen when these issues are fixed. Perhaps HMD will fix them with the July Security update.