So far, it is said that this particular update has been made available to folks living in Poland and Panama (hmmm, ‘P’ seems to be a recurring theme here) where it will feature the firmware versions known as G531FXXU1AOF7 and G531MUBU1AOFB, respectively. As for the respective files, they would be approximately 730MB in size, and will be accompanied by the standard slew of security and stability improvements, in addition to changes that will affect not only the interface in the lockscreen, but also the notification area as well.
I suppose those who own the original Galaxy Grand Prime will be far from happy with this bit of news, since their handsets continue to remain on Android 4.4 Kitkat while even a “Value Edition” model makes the jump straight to Android 5.1.1 Lollipop.