Posted on: April 28, 2017, 07:37:31 AM
The template itself has already been fully tested with Joomla 3.7.0 and up to Php7, and is working with no issues. Please be sure you are running the latest version of Vertex on the template.
"0 - Using $this when not in object context"
----I am not sure what that error message means, but it most likely pointing to a syntax error. I would suggest disabling all third party extensions, component, plugins, etc. to see if one of them is causing the problem. Upgrade errors almost always happen because of third party extensions.
Regarding modules and articles not opening in the backend, the template does not control any of this. A template only stylizes the site. Those functions are entirely handled by Joomla itself. I would suggest posting that on joomla.org's forum boards to see if they can debug the issue as this pertains directly to the CMS itself and not the template.