Had some time to play, try this:
#include <Array.au3>
Global $aFileListVers[0]
Local $aFileList = _FileListToArray("C:\WB Resources\FAINT_DONT_LINK_THESE\", "*.exe", $FLTA_FILES, True)
For $i = 0 To UBound($aFileList) - 1
$aFileVersion = FileGetVersion($aFileList[$i], $FV_PRODUCTVERSION)
_ArrayAdd($aFileListVers, $aFileVersion)
Next
_ArrayDisplay($aFileListVers)
_ArraySort($aFileListVers, 1)
_ArrayDisplay($aFileListVers)
MsgBox(0, "Version", "Highest Version: " & $aFileListVers[0])
I did notice that not all exe's have a version as such that autoit can find it this way.
So check yours first using Context Menu (Right Click) Properties/Details and look at Product Version.
If its empty this will not produce anything.
This one for instance has a File Version but no Product Version so you would have to change the FileGetVersion Parameter