When you turn your PlayStation 4 on next, you're going to be prompted to do
IGN Game Reviews - PS4 Video Review
Firmware update 1.74 is... well... boring, at least if you're looking for new and exciting things for your PlayStation 4 to do. "System software stability during use of some features has been improved" is literally the one and only patch note for the update.
There's not much else to say. Consider this a friendly reminder to download that firmware update now (or as soon as possible) so you're not interrupted when you actually want to play.