Is it necessary to upgrade ionic from v2?


I’ve just join an ionic development team and we have some app built with ionic 2x and cordova-android 6x, the development platform (node, cordova cli) is also very old. My though is to update cordova-android and the development platform to get the latest security updates (node modules). Since we are OK with the current set of features provided in ionic 2x, I dont want to update it at the moment. My concern is that ionic 2x may be end of life and no more security update is available. Do I have to update ionic to v4 just to be secured ? The application was written in js, not typescript btw.

Hope to get some feedback from the experienced