We used to use functions "LinkTrackVars" and "LinkTrackEvents" in SDK 3.x. So, wondering what would be the equivalent functions we need to use for SDK4.x. Is there any alternate way of implementing or using these functions in latest SDK ?
The equivalent functions would be trackState and trackAction methods.
With 4.x you can no longer assign variables such as events, eVars, props, heirs and lists directly. The SDK uses context data and processing rule to may your app data to Analytics variables for reporting.
Here are couple of documentation links referencing the above and further information.