Twig_Error_Runtime on install

Hi there, can't seem to get beyond this error, have installed the blog skeleton package locally on linux mint machine (ubuntu) with lamp. Apache is working alright, so is php. But all I get when browsing to localhost/grav-blog is this message "An exception has been thrown during the rendering of a template ("defined() expects exactly 1 parameter, 2 given") in "partials/blog_item.html.twig" at line 3."
So is this an apache config issue? I have set DocumentRoot in apache2/sites-enabled/000-default.conf to the same path in my home dir as in apache2.conf.
Any help appreciated!

Please update Grav and Antimatter theme. Not sure when you grabbed the skeleton package, but there was a problem over the weekend where the package contained an unreleased version of Antimatter, that caused this problem.

I just downloaded the newly updated package (from today) and it works fine.

Sorry about that!

Thanks, I'll try that