Matt can answer in more detail, but I don't believe there are any major changes to the hull. The i14T recently had the bow enclosed storage area removed & replaced with bungees. That's the last major hull change in the inflatables I can recall.
The difference may be in the Mirage drive. A 2011 model would probably be a 2010 production V2, which is basically the current version. The V2 has been used since 2009 production. There have been some refinements to the drive since then, so a 2010/2011 drive may not have all the latest revisions. It would still be 95% up to date I'd guess. The fine points of the Mirage drive revision history are above my pay grade. There's a TON of Mirage drive info in the forum, so you can research further if it helps your decision.
One odd thing I discovered with my i12S is that the hull was manufactured in November 2007 even though it is a 2011 model! The HIN (Hull Identification Number) ends in "K711", which indicates it was manufactured in November (K) of 2007 (7) and is a 2011 (11) model. The MSO (Manufacturer's Statement of Origin) states it is a 2011 Model sold on a 12/02/2007 invoice.
So, assuming this is correct & Hobie does not use some other HIN system for the inflatables, the 2011 hull or the 2014 hull may well have been manufactured many years prior to their "model year" anyway.
Hope this helps!