Have you chosen the Absolute or relative option for your comment date?

Absolute... but if I chose relative i get very strange looking date like this: 2013-12-28 10:00:49
Thats no relative time stamp in my opinion, is it?

Do you use overrides for this module?

no

Clean your site's and browser's cache and check again.

I found the files I have to change now:

Its in the de-DE.mod_k2.j16.ini for the module output and in the de-DE.com_k2.j16.ini for the component output.
Both files are in the administrator > language folder...

So now i want to add some text to the translation. But the way I did it was not accepted... Why not?

I changed
K2_DATE_FORMAT_LC2="l, d F Y H:i"
into
K2_DATE_FORMAT_LC2="l, d F Y um H:i"
and the output is like
auf Donnerstag, 30 Januar 2014 00000001 11:52.

Why?

You can't have words other than date parameters in this date language definition.

In case you need to add words I'm afraid that you have to break your date in two definitions, like

K2_DATE_FORMAT_LC2="l, d F Y"
K2_DATE_FORMAT_LC3="H:i"

and also change the file mod_k2_comments/comments.php (better create an template override of the module and make the modification there. Just copy the mod_k2_comments/tmpl/comments.php to templates/your_template/html/mod_k2_comments/).

Then locate this

<?php echo JText::_('K2_ON'); ?> <?php echo JHTML::_('date', $comment->commentDate, JText::_('K2_DATE_FORMAT_LC2')); ?>

and change it to this

<?php echo JText::_('K2_ON'); ?> <?php echo JHTML::_('date', $comment->commentDate, JText::_('K2_DATE_FORMAT_LC2')); ?> um <?php echo JHTML::_('date', $comment->commentDate, JText::_('K2_DATE_FORMAT_LC3')); ?>

Ok thanks so far. That works for the module output. But how can i change the same thing in the component output? I tried to change the item.php in com_k2 > templates > default as i did for some other changes before but the code you told me doesn't work over here, even though the code seems to be the same as in the comments.php.

Did you update the language files de-DE.com_k2.ini with the new language definitions as well?

Yes!


Btw: Why do I have to enter a captcha code everytime I post something? That is really annoying...