整理一下CentOS 各个版本的对应关系，表格引自官网：https://wiki.centos.org/Download
Archived Versions CentOS Linux 7 ReleaseBased on RHEL Source (Version)Archived Tree7 (2003)7.8Tree7 (1908)7.7Tree7 (1810)7.6Tree7 (1804)7.5Tree7 (1708)7.4Tree7 (1611)7.3Tree7 (1511)7.2Tree7 (1503)7.1Tree7 (1406)7.0TreeCentOS Linux 6 ReleaseBased on RHEL Source (Version)Archived Tree6.106.10Tree6.96.9Tree6.86.8Tree6.76.7Tree6.66.6Tree6.56.5Tree6.46.4Tree6.36.3Tree6.26.2Tree6.16.1Tree6.06.0TreeCentOS Linux 5 ReleaseBased on RHEL Source (Version)Archived Tree5.115.11Tree5.105.10Tree5.95.9Tree5.85.8Tree5.75.7Tree5.65.6Tree5.55.5Tree5.45.4Tree5.35.3Tree5.25.2Tree5.15.1Tree5.05.0TreeCentOS Linux 4 ReleaseBased on RHEL Source (Version)Archived Tree4.94.9Tree4.84.8Tree4.74.7Tree4.64.6Tree4.54.5Tree4.44.4Tree4.34.3Tree4.24.2Tree4.14.1Tree4.04.0TreeCentOS Linux 3 ReleaseBased on RHEL Source (Version)Archived Tree3.93.9Tree3.83.8Tree3.73.7Tree3.63.6Tree3.53.5Tree3.43.4Tree3.33.3Tree3.13.1TreeCentOS Linux 2.1 ReleaseBased on RHEL Source (Version)Archived Tree2.12.1Tree