UPDATE RESOLUTION LINUX ED UPDATE SOFTWARE SYSTEM ON OPENVZ

Hi, I need to update the resolution on my ubuntu system installed on openvz , is configured as a resolution of 1400 x 900, but link always in vnc + ssh, the maximum resolution that I can see is 1024x768 , should I increase the resolution to at least 1400 x 900 with 32 bit color. Also resolve the problem of ubuntu that receive the most update, since the ubuntu system after it has been updated to the latest version 17.04 this last update required a kernel update to version 3 but as the system is installed on an openz the kernel the kernel is the last supported is version 2. I would like to solve this problem, in order to continue to upgrade the software of ubuntu