On few of the plugins :
- SJ Mega News for K2
- SJ K2 Slider
- SJ K2 Slick Slider
- SJ K2 Slider
- SK Mega News for K2

We are getting 500 error and module can't be saved or edited.
What could be a reason for this? Where could we look for error message?
Joomla 3.8.1 Stable, SJ University 2.0.1

EDIT:
I have noticed there is also an error message in the title of the page, and is as follows: "Error:0 Call to undefined method K2HelperHTML::loadjQuery()"

Thank you

Downgraded K2 to 2.7.1 - now modules are working as expected.

Dear rok.sajovic

This issue relate to k2 2.8.0
to fix this issue when use our module with k2 2.8.0 refer below, it is the same for all the sj k2 module

please edit .xml file of the each module by find the code

in /httpdocs/modules/mod_sj_k2_slider/mod_sj_k2_slider.xml and find:

<field name="item" type="item" default="" label="K2_ADD_ITEMS" description="K2_USE_THIS_TO_ADD_ITEMS_TO_THE_LIST_BELOW"/>
<field name="items" type="items" default="" label="K2_DRAG_AND_DROP_TO_REORDER_ITEMS" description="K2_DRAG_AND_DROP_TO_REORDER_ITEMS_CLICK_THE_REMOVE_ICON_TO_REMOVE_AN_ITEM_FROM_THE_LIST"/>

=> change to:

<field name="items" type="k2modalselector" default="" label="K2_ADD_ITEMS" description=""/>

thanks

I've upgraded K2 back to 2.8.0 and applied the fixes to module xml files - all well now. Modules work and can configure them. Thanks.

Dear rok.sajovic

If you have any the problem please contact us.

thanks