Comment 4 for bug 1455137

Conrad changed the following in his language pack and that resolved the problem. If there is a more permanent fix that would be great.

In
/langpacks/de.utf8/lang/de.utf8/langconfig.php

changed line
$string['calendar_timeFormat'] = 'hh:mm';

to
$string['calendar_timeFormat'] = 'HH:mm';

Now the time is shown in 24-hour format.