Like the other folks have said the Sony BDP-S1100 does not play 4k discs. Does a nice job on dvd's & Blu-rays. I was told when i bought the player not to have a firmware update because it will erase the all region setting.
I bought my Sony BDP-S1100 region free player from Amazon a few years ago and it plays everything from all regions. No issues and nice picture with both dvd & Blu-ray