object returns a read-only Long value indicating the major version number of an application to which you have set a reference.
expression.Major
expression Required. An expression that returns one of the objects in the Applies To list.
Remarks
The Major property is available only by using Visual Basic.
The Major property returns the value to the left of the decimal point in a version number. For example, if you've set a reference to an application whose version number is 2.5, the Major property returns 2.
Example
The following example displays a message with information about all the references in the current project.
Dim r As Reference
Dim strInfo As String
For Each r In Application.References
strInfo = strInfo & r.Name & " " & r.Major & "." & r.Minor & vbCrLf
Next
MsgBox "Current References: " & vbCrLf & strInfo