Fatal error

Hiho!

My wordpress installation did not have the theme and plugin editor. So I searched for a plugin that would enable this functionaility.

I have installed yours (no problem) and then activated. As a result I receive the following:

Fatal error: Call to undefined function is_site_admin() in /homepages/31/d513689962/htdocs/clickandbuilds/HamburgRelocation/wp-content/plugins/enable-theme-and-plugin-editor/enable-theme-and-plugin-editor.php on line 19

What can I do?

Kind regards
Kerstin

https://wordpress.org/plugins/enable-theme-and-plugin-editor/