WARNING: Security updates for your current Hardware Enablement Stack ended on 2016-08-04

This gem needs some words.
linux-generic-lts-utopic works and has feature in it that make it compatible with kernel work I and doing. 3.13 and 4.4 series kernels can not be made compatible without many months of work.
Are the MATE team going to do what uBuntu are clearly not going to do and support the 3.16.x kernel for the full LTS lifespan of MATE 14.04 LTS ?
If you are, what changes do I need to sort this ?

Ubuntu Mate LTS is supported for three years and not five. Kernel support:

https://www.kernel.org/category/releases.html

Mark, your user icon looks really good…:grinning:

Seriously though, I also tried to upgrade to a supported kernel (in UM 14.04). I installed version 4.6 and things seemed OK at first. Later I noticed that it broke sound in Skype (terrible lag). So now I am back to 3.16.

When I downloaded Mate-14.04-LTS it cleatly stated on the web site that it would be supported to 2019. besides, it is 2016 - only two years out so even with your logic, I have another 6monthes to go, not -1 month.