Trend 2015 or Norton 2014

I'm looking to purchase either Premium Security 2015 or Norton Security.  From what I can gather Trend's product was recently released, but Norton's current product was released Sept. 2014???

My question is, if I purchase Norton Security (1 year) now when their new version comes out.  Do I have to buy the new version or would I automatically be eligible for the upgrade?  I'm assuming the new version will be released before my 1 year subscription is over.

Thank you.