The release of Varnish Enterprise version 6.0.13r11 and 6.0.13r12 have been removed from the package repository. This is due to a regression in the latest releases.
The issue that has been uncovered can lead to backend TLS backend traffic hanging, causing timeouts and delays in serving traffic. This can severely affect the Varnish Enterprise server throughput.
We do not recommend anyone to use the 6.0.13r11 or 6.0.13r12 versions at this time. Users that have installed these versions may want to upgrade to version 6.0.13r13 if they are experiencing issues.