The release notes for v1.6.10 can be found here.
Rancher server has 2 different tags. For each major release tag, we will provide documentation for the specific version.
rancher/server:latesttag will be our latest development builds. These builds will have been validated through our CI automation framework. These releases are not meant for deployment in production.
rancher/server:stabletag will be our latest stable release builds. This tag is the version that we recommend for production.