I solved that same Python 2.6 issue on CentOS 6 with Software Collections. Software Collections are kinda weird, and I’m not sold on using them for everything, but they are perfect for solving this kind of problem where you need multiple versions of something on the same machine.

I also included how I automated this to do auto-renewal. I really like how each LetsEncrypt has made the renewal process once you figure out how to get the cert issued the first time.

https://thelastcicada.com/solving-the-python-2-6-issue-for-letencrypt-on-centos-6