GTM and LTM firmware levels

I have completed an upgrade of our LTMs from 10.2.3 to 11.4.1 and now need to do the GTMs. However the release notes for 11.4.1 state zone syncing issues on the GTM and thereby need to avoid - the question is what version should i go to, can the GTMs be on a higher veriosn than the LTMs or should they be on lower?

Thanks