Today y bought Avendor for Joomla and I have encontered that the joomla version that comes in the quickstart (3.4) is not compatible with PHP7.
As I've seen in many forums:
f you are calling Joomla\String\String directly you must change your calls to Joomla\String\StringHelper (added to Joomla 3.5). For Joomla 3.4 and earlier compatibility you should call the deprecated JString class instead (in 3.4 it extends the Joomla\String\String class and 3.5 Joomla\String\StringHelper)
I cannot ask to the hosting for an older version of PHP.
Do you have a quickstart with a newer versions of Joomla than 3.4
I have tested to update the Template and Joomla at the moment but without any success ... :-( the Template is working well but some Extensions, for example Roksprocket don't work anymore. Really really sorry about that! But of course, please feel free to contact Envato and you will get a Refund!
Simply write that "Oli from WS-Theme" has said that and my Partner will accept the Refund. Really sorry but currently it's too much work for me to bring up the Template to PHP7 ...