I noticed that in the version 1 of the API there was a field called "EmailType" on the contact object that allowed specifying HTML or Text as the user's email format preference. I can't find it anywhere in the version 2 documentation here.
If it is one of the things that has not been added yet then I was expecting it to be on the list of unsupported features here but did not see it there either.
I'm sorry if this has been posted before but the name of the field makes it a little hard to search for.
That's a great question. We've removed that field completely from our Contact Management system and are currently returning it in the v1 solely for backwards compatibility purposes. At this time, we send an HTML and Text version of every email to every contact, which is the industry standard. Now, each subscribers client settings will decide which version to show. A subscriber can configure their phone to display text, their desktop to display HTML and any other configurations they want and it will "just work".
Specifying which version to send used to be an industry best practice. However, due to the flexibility of email clients, advances in technology overall and increases in download speeds on all fronts, this is no longer the case. Sorry for any confusion this may have caused!