Roundcube has released a security update for the 1.7 and 1.6 branch, 1.7.2 and 1.6.17
If you are at the 1.6 branch, you can update to 1.6.17 by using these instructions as a guide. Just be sure to change to 1.6.17 where appropriate.
why can’t hestia update this for me?
It will do on next release.