This is the next maintenance release of Wireshark 2.6. The repository will bring you to version 2.6.6 automatically.
If you haven’t already added the 1310nm.net Wireshark repository, follow the instructions in Wireshark on CentOS7 (TL;DR version). Run yum update and get the latest repository information, then upgrade to the most recent Wireshark version.
epel repositories to support libnghttp2 for HTTP/2 support. yum install epel-release prior to installing Wireshark will help here.