No, for example on Android and iOS the APIs for when you connect to a server the hostname is a string. This hostname can be either an ipv4 address, an ipv6 adress, or a domain. The BSD sockets API on the other hand forces each application to implement this themselves and a lot of them took the shortcut of only supporting ipv4.

It isn't about upgrading one protocol to another but about having the operating system abstract away the different protocols from the application.