www.makemkv.com

I am running version 1.8.9. I tried installed 1.8.10 and while it said successful it kept saying the old number was installed and told me a new version as available.

I just left it but I have now tried 1.8.11 and I get the same.

Can anyone help please

Most likely, you either had a copy of MakeMKV running in memory, OR you do not have the same privileges when you're doing the upgrade that you had when you installed the program originally.

Late model versions of MakeMKV will ask to uninstall the old version before installing the new.