Utilising the Current (and Actual) check box within the Version Settings allows the use of CURRENTVERSION() and ACTUALVERSION() in calculations, in SELECT statements and ISCURRENTVERSION and ISACTUALVERSION() for Boolean checks. Current version also acts like a top level for Versions; if you have a source module with versions (and Current ticked), in a target module without versions, the value from the current version will automatically be returned without needing additional functions or SELECT statements
Related Rule:
2.02-14 Avoid using SELECT
Questions on this topic? See 1.02-01 Use "Current" in Version settings in our Planual forum.