Version tab allows you to change the ASF version used in the project.
When Trigger upgradation of modules is checked , all the available ASF versions greater than or equal to the current ASF version in the project will be listed. ASF conversion wizard is launched for continuing conversion of source files and the same is discussed in the section ASF version conversion wizard
If user has modified any ASF files in the project, then a warning message would pop up (as shown below), displaying the list of modified files. Double click the file item to show the changes made on the original ASF file. Note: User has to configure the File Compare from Tools-> Options-> Atmel Software Framework from the menu, provide any (e.g.: WinMerge) application that can be used for comparison. For more details, refer section ASF File Comparison
It is not recommended, because it does not guarantee successful compilation of the project.