One of the best features of Flow is the concept of properties.
There are two kinds of properties, those created by the user or application, called Custom Properties, and those that are part of the Flow definition, called Intrinsic Properties.
Here are some of the differences in these two types of properties.
Custom Properties (as with all object names) are case preserving but not cas- sensitive.
Intrinsic Properties are case-sensitive.
The following Custom Property retrievals all return the same result:
The following Intrinsic Property retrievals error on the second, all lower-case, property name:
Some Intrinsic Properties are immutable, their value cannot be changed.