On November 30, 2020, CentOS will stop supporting CentOS 6 on all systems, including your server. At that time CentOS will no longer provide bug, security, or feature updates. We encourage you to migrate to a server using CentOS 7 before November 30, 2020.

わかってはいたけど地味に痛い。
どうしようかねぇ・・・