What is the difference between URL Path and URL Path (Previous) fields shown in Nintex Worfklow Editor?
you see these "previous" values only in the start conditions of a workflow and afaik it's quite equal to before and after properties (regarding item changed event receivers).
That means your previous value fields hold the values before an item was changed. The "normal" values store values after the item was changed. This way you can check what was modified in the item and e. g. only start your workflow when a certain column was changed.
Hope this helps.
in addition, you have to know that the conditional start is the only point where you can do some logics with previous values of the item's fields, during the workflow you have access only to the current values.
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