I got an update on my SGH-i257M [Rogers, Canada] a month or more ago [perhaps a couple or a few months] but well after the KitKat 4.4.2. I did not keep track of the date. It said "for more reliability" or something similar. It updated more than 170 Apps. That was the only part of the process that i really watched, the counter increasing.
I visit all of the S4 mini forums every day. No one else has posted any info about this update even tho i did ask about it. I feel like i am the only person in the known universe who received this update.
My phone has not dropped service since this update whereas previously the phone was very unreliable.
I had returned to the Rogers store with it several times, most times receiving specifically incorrect but always unhelpful info from the counter people. Three times they sent it off to the Samsung repair depot in Toronto with an incorrect description of the problem. The repair people each time did a reset or a re-calibration or whatever that did not have any effect on the problem.