The first batch of renumbering began on September 15 with Viettel’s 0169 prefix switch to 039, Vinaphone’s 0124 to 084, Mobifone’s 0120 to 070, Vietnamobile’s 0186 and 0188 to 056 and 058 respectively, and Gmobile’s 0199 to 059. For example, the phone number 0169-1234567 will now become 039-1234567. The remaining 11-digit numbers will have their prefixes changed in separate batches over the coming days until October, 7 while ten-digit numbers that begin with 09x will not be affected. Both the old and new numbers will be functional until November 14, 2018, after which, calls to the old numbers will receive an audio message informing users of the change in number. The audio message will cease to be played after June 30 next year. Viettel, Mobifone, Vinaphone and Vietnamobile have announced that their subscribers can use carrier apps on their smartphones to automatically update their contacts. Viber and Zalo, the two major instant messaging services in Vietnam, also announced that they will provide automatic support the change in account numbers of their Vietnamese after the back-end change is completed. For users of feature phones, the carriers stated that support will be provided at their outlets. According to the Vietnam Telecommunications Authority, 60 million subscribers are affected by this change, with Viettel accounting for more than half of the total number of subscribers.