I am new to working with Constant Contact's API.  I have been tasked with converting our internal .Net Constant Contact service to .Net Core.  All we are doing with the service right now is pushing emails from our different sites into CTCT.  I am not seeing any reason for upgrading to v3 API, I was wondering if there was some compelling reason to upgrade.  Is there an end of life for v2 API?  Is there security advantages to v3?   So if I do upgrade to v3 API, how exactly is that done?  I have seen the documentation about if we are hosting the data ourselves, which we are not, how to add the UUID's.  But we are allowing CTCT to host all the email lists.  It is my understanding I will need to create a new APIKey & AccessToken for v3 API, but the username/password I was given to access constantcontact.mashery.com is not working on the site to create the new APIKey & AccessToken. There seems to be some fundamental piece of info I am missing here, can someone fill me in? ... View more