Well since they have just updated the 15" inch (about 2 - 3 weeks ago) and the 13" inch (2 Months ago).... so i doubt there will be any upgrades until 2016. Also 2016 will be the last of the current design.
I've heard some talking about the 2017 version of the Macbook Pro having a design change. So i will be definitely purchasing a new Macbook in Late 2016.
Any upgrade this year will likely be just a slight spec bump in clock speed. As Matty mentioned, they were already updated 2 months ago with force touch trackpads. I wouldn't expect any big overhauls for a while