_satellite.data

The usage of_satellite.data in DTM tends focus around the_satellite.data.customVarsobject. This object was never intended to be accessed directly, but the system allowed it, so people did it.
Remedies:
If your DTM implementation set data elements in code by setting keys directly on the _satellite.data.customVars object, you can replace those calls with _satellite.setVar(<data element name>, <data element value>).
Below is an example in code.
//Crusty old stuff in DTM
_satellite.data.customVars.checkoutStage = "Shipping Info";
//Shiny new stuff in Launch
_satellite.setVar("checkoutStage", "Shipping Info");
If your DTM implementation accessed values directly from within the_satellite.data.customVarsobject, _satellite.getVar(<data element name>) can be used instead.
Below is an example in code.
//Crusty old stuff in DTM
var checkoutStage = _satellite.data.customVars.checkoutStage;
//Shiny new stuff in Launch
var checkoutStage = _satellite.getVar("checkoutStage");