The latest CentOS version is CentOS7 (version 7.7.1511)
Others CentOS version under support – CentOS6 (version 6.6.8) End Of Life (EOL) CentOS
CentOS 5 — version 5.5.11 –> 31st March 2017
CentOS 4 — version 4.4.9 –> 29th February 2012