Error message accessing survey backend after update to 5.8
I have just updated to latest version of Community Surveys and now when I try to access survey in Administrator area I get the following error:
Call to undefined method Joomla\CMS\Document\HtmlDocument::getWebAssetManager()
I tried it on a dev site and same problem.
I have updated JCE just in case it was that as was suggested elsewhere.
Any idea how to fix access?