On the http://rimuhosting.com/cp/vps/kernel.jsp page you can now select the 4.0 kernel for your VM. Includes: OverlayFS, carries on with support required for Docker and SELinux, lots of new nf/eb table options, openvswitch, nfs4 support and too many other new kernel tweaks to mention. Plus newer, fresher kernel code with lots of fixes to bugs (which likely are not affecting you).
We have only produced a 64 bit kernel this time around. That should be fine even for 32 bit distros.
If you like being on the latest and greatest then this experimental kernel is for you. If it doesn't work out, restart your VM with our very stable and tested 3.12 kernel. (Also: let us know if you needed a kernel option we do not have enabled. Also: we have a pv-grub option should you need to have full control over every module in the kernel.)
If your server is running well and you are happy with things, feel free to leave your kernel as-is.