As you probably saw it, we released CentOS 7.7.1908 for all architectures earlier today : - https://lists.centos.org/pipermail/centos-announce/2019-September/023405.htm... - https://lists.centos.org/pipermail/centos-announce/2019-September/023406.htm...
Just after that we regenerated the koji internal repos to use that new release so it's now done : https://cbs.centos.org/koji/tasks?state=all&owner=koji&view=flat&...
That means that all your builds for CentOS 7 will be built against 7.7.1908 content.