• First add a custom field, and make it of type Version Dropdown Searcher
• Create an issue, and select a version in the custom field
• Check the email, it will contain text such as "Scheduled release: 10001 (was: 10000)"

10000 is obviously an internal identifier, the actual release name is more like "TMAP-1.8.3"

Btw, it was selected as a Global custom attribute. And yes, we use about three version fields per issue.