According to https://github.com/pimutils/khal/releases there is a new version that fixes a critical bug.
commit 0b1317c792c717e86b5cf8a9d0c6e340574fd134 Author: Amy Winston <amynka@gentoo.org> Date: Sat Dec 24 13:04:35 2016 +0100 app-misc/khal: version bump 0.8.4 bug #603086