I have the ipv3 and have taking it apart and the wire is soldered to the 510 so that is confirmed also if you start having jumpy resistance, take a q tip and clean the
threads inside the 510 of the
ipv and this will help it quite a bit I find mine gets really dirty over a couple weeks so if it starts jumping I clean it up good as well as keep your atomizer pins and
threads good and clean and it will not happen.