The documentation[1] states that OpenShift Container Platform 4.18 is compatible with RHEL 8.8 or newer, but documentation[2][3] mentions RHEL 8.6 instead.

[1] https://docs.openshift.com/container-platform/4.18/release_notes/ocp-4-18-release-notes.html#:~:text=OpenShift%20Container%20Platform%204.18%20is%20supported%20on%20Red%20Hat%20Enterprise%20Linux%20(RHEL)%208.8%20and%20a%20later

[2] https://docs.openshift.com/container-platform/4.18/installing/installing_aws/upi/upi-aws-installation-reqs.html#:~:text=Red%20Hat%20Enterprise%20Linux%20(RHEL)%208.6%20and%20later.

[3] https://docs.openshift.com/container-platform/4.18/installing/installing_aws/upi/upi-aws-installation-reqs.html#:~:text=RHEL%208.6%20and%20later%20%5B3%5D

    1.
    2.
    3.