HMD has confirmed that the Nokia 7 Plus smartphone will get support for dual VoLTE functionality. The confirmation came from chief product officer Juho Sarvikas. Thanks Sid for the awesome review and don't worry, 2nd sim will support LTE shortly! Juho Sarvikas (@sarvikas) May 4, 2018 The feature will allow users of the device to use both their SIM cards for 4G LTE access. Sadly, an exact timeframe wasn't revealed by the executive, but 'shortly' suggests a waiting period measured in weeks rather than quarters. Source
Source: https://www.gsmarena.com/nokia_7_plus_to_soon_get_dual_volte_support-news-30883.php