OS Property won't install on my Joomla site v3.6.5

When I go to the Upload & Install Joomla Extension page and select com_osproperty.zip I get the Joomla cursor and then it just redirects to:

administrator/index.php?option=com_installer&view=install

and I'm stuck on the same page, nothing got installed.

Hi Ron,
Please submit ticket and send your site url with super admin account. I will help you to install and configure OS Property extension for you
Thanks
Dam

Actually I finally got it to install (not sure how), but I'm having other issues. I installed sample data, and on the homepage when I hit search with default filters I get this error page:

Call to undefined method JApplicationSite::isClient()

Also in the back-end when I hit "Manage Properties" within the component I get this error:

0 Call to undefined method JApplicationAdministrator::isClient()

I've installed this on a fresh Joomla install and it works fine. However I would like it to work on this existing site, but I'm guessing some other component is possibly breaking it. Feel free to make any changes you need to, this is just a staging server, and I have a backup of the site. I'm creating the ticket now.

Thanks!

Hi Ron,
I am afraid that you should upgrade your Joomla vesion to newer version, because your current Joomla version 3.6.5 is too old, and it doesn't support some new core functions (is being used in OS Property)
Thanks
Dam