There has been a new release of Roundcube: https://roundcube.net/news/2016/04/20/updates-1.1.5-and-1.0.9-published
I have updated the OBS package with this version, and you can run
yum update or
apt-get update && apt-get upgrade depending on your Linux OS.
For more details about how to create such an update, or how to work around the issue when Roundcube has been updated in the OS already but not yet in the Kolab OBS, have a look at my older blog post: http://www.pokorra.de/2015/10/new-roundcube-1-1-3-release-for-kolab-3-4-updates/
New Roundcube 1.1.5 release for Kolab 3.4 Updates