The Webmail theme in use is LookOut, confirmed by KeyMap=LookOut
The KeyMap entry stores the keymap, not the theme. The key that stores the default theme is "Theme"
The file WC.INI also contains per-domain and per-user sections confirming the same permissions
The worldclient.ini file should not have per-domain and per-user sections. They should only be in the domains.ini file.
We attempted adding EnableCalendarPublishing=Yes manually as well
I can't find where this key is used for anything.
I tested using MDaemon 24.0.0 and in the Lookout theme I'm able to publish a calendar by going to Options / Folders, click the Share folder icon next to the calendar folder you'd like to share and then click the Public Access tab.
It should look similar to this:

If the Share Folder column is empty, it means you do not have shared folders enabled. Open the MDaemon user interface and go to Setup / Public Folders / Public & Shared Folders and check the box for Enable Shared folders. Then log out of webmail and log back in.
Also check to ensure:
- the MDaemon\WorldClient\Domains.ini file [Default:Settings] section has this set, EnablePublicCalendars=Yes
- the MDaemon\Users\$DOMAIN$\$MAILBOX$\WC\User.ini file does NOT have this set, CanPublishCalendars=No
If you are still not able to publish a calendar:
- What is the exact version of MDaemon you are using?
- Are users able to publish a calendar using the WorldClient theme?
- What steps is the user taking in the lookout theme to attempt to publish the calendar?
- Please upload a copy of your MDaemon\app\mdaemon.ini, MDaemon\WorldClient\worldclient.ini, MDaemon\WorldClient\domains.ini, MDaemon\Users\$DOMAIN$\$MAILBOX$\WC\User.ini for the user that is attempting to publish the calendar, and a copy of the webmail log that includes the time period that the user attempted to publish the calendar. Also let us know the email address of the user and the approximate time they attempted to publish it, so we can find it in the logs. Put all the info in a zip file and upload it to https://mdaemon.sharefile.com/r-rc3922c1eed334d4dbf5e34f0bd04ccd6, once the upload is complete, let us know the name of the file you uploaded.