Hello edmoncu,
Yes, as described in the release notes for 2.13.0, CentOS7, Red Hat 7, are required to use Python 3.8 now, and it is done using SCL, and the installation instructions have been updated to include enabling the SCL repository.
https://openvpn.net/vpn-server-resources/release-notes/
"On CentOS 7 and Red Hat 7, we now require Python 3.8. This is done by using the SCL repositories. The installation instructions for these operating systems have been updated to include instructions to enable the SCL repositories."
Also FYI, you should probably start to plan to move away from CentOS 7 / RHEL 7 as 2.13.0 will most likely be the last major release to continue to support those platforms. It's already extremely difficult to marry the concept of modern security standards with an operating system using software from ~10 years ago, but moreover, the EOL date of CentOS 7 is creeping up - June 2024.
Kind regards,
Johan