We just published updates to all stable versions 1.x delivering important bug fixes and improvements which we picked from the upstream branch.
The updates primarily fix a recently discovered vulnerability in the virtualmin and sasl drivers of the password plugin (CVE-2017-8114). More details about this vulnerability will be published soon by the reporter. Security-wise the update is therefore only relevant for those installations of Roundcube using the password plugin with either one of these drivers.
See the full changelog for the according version in the release notes on the Github download pages: