Why does Apple persist in downloading the complete OS when it wishes to distribute an upgrade? Other software producers simply download a patch. My Internet data allocation is 17 GB/mth. I am not one of the fortunate whose employer supplies them with unlimited data. Should I exceed my allocation, my ISP charges exorbitantly for additional data allowance, so I keep a close eye on my usage during the month. Apple sending me 2 GB of OS instead of a few MB of patch can blow a substantial hole in the data I can use for the things that are more urgent. See what I mean?