What is the difference between iteration with release type Project Release under Timeline and Releases (tab)?
One answer
The Iteration is used for Planning when a Work Item should be done. It's the enumeration behind the Planned For field in the WI's.
The Release is used for filing defects against a release version opf the product. Used as enumeration in Found In field on the Defect Work Item.
In Build System you can reference a build to a Release value or create a new Release value which you then can use as Found In.