CD 4.16 (last CD version) is a patch (released by @Veladarius) to make CD 4.15 compatible with DDi 4.xx as CD 4.15 only supports DDi 3.xx   However, if you are sure your CD version is compatible, you can add it to the CD compatible versions list (iCDxCompatibleVer) bellow.   If it is 4.09 enter it as an integer 409. That should stop that message box from appearing.