H2O version 2.0.4 / 2.1.0-beta3 released including a vulnerability fix Today we have released H2O version 2.0.4 / 2.1.0-beta3, which includes a fix to a vulnerability (CVE-2016-4864). Users of H2O are advised to update immediately. For detail, please refer to the issue page at https://github.com/h2o/h2o/issues/1077.