We have made further upgrades to our site install code and this time there has been key functionality added to enhance user tracking. Though this functionality in the API is still in its early days and there are other ways in which we track users, this upgrade will essentially help deliver better ROI for publishers as advertisers are willing to pay for better metrics and results.
This is an important enhancement but ZestADZ is completely backward compatible with the previous code. So you can choose to upgrade or choose to remain with your existing site install code.
We would however would strongly recommend you going in for an upgrade of the site install code.
If there are any questions, write to us at support [at] zestadz.com