[Koha-devel] Koha uninstalled by Debian Linux "update"

Just a heads up that a recent "update" by Debian Linux removed the application Koha - my apache and data files apparently are fine. How do I reinstall Koha without damaging or overwriting my data? If anyone has any experience with this, please let me know. If you see the red "burst" in the upper right hand corner, only do the safe install .. or else...