I can still see 6.2.4 as an available download in my own support area. (Forget about 6.2.3, X1 replaced it.)
If you can't see it, then you may need to use the various links in there to report your missing information to the official support team. This place is effectively user-to-user self-help that isn't designed to deal with your sort of query.
If you can't see it, then you may need to use the various links in there to report your missing information to the official support team. This place is effectively user-to-user self-help that isn't designed to deal with your sort of query.