CentOS - Nov 2018 - Centos 6.9 Ipset broken after installing xtables-addon

I have managed to break my system by installing xtables-addons-1.37. Now
ipset does not work.
"Kernel error received: Invalid argument"

I built the addon from source on my centos 6.9 system as per instructions
for centos 6.

It looks to me that xtables-addons has built and installed a ipset-4
extension due to my kernel:

2.6.32-754.6.3.el6.x86_64

I already had ipset v6.11 installed and now both do not work.

The README indicated that I need a kernel > 2.6.35 which I presume is the
problem.

This now has become a major problem for me as I rely on ipset.
Anyone suggest what I might do to fix this problem?

Thanks,

/Geo