Just like their previous PS4 OFW update, today Sony released PlayStation 4 System Software / PS4 Firmware 4.06 Update which once again 'improves' the quality of the system performance by patching more security holes as confirmed by @flatz on Twitter. 
Download: PS4 Firmware 4.06 Update (US) / PS4 Firmware 4.06 Update (EU) / PS4 Firmware 4.06 Update (UK) / PS4 Firmware 4.06 Update (AU/NZ) / PS4 Firmware 4.06 Update (JP)
Main features in system software update 4.06
Needless to say, don't update to PlayStation 4 Firmware 4.06 if you wish to run PS4 backup games and homebrew whenever a public PS4 jailbreak exploit / loader is released... and keep an eye on the PSProxy v4.1.0.0 PS4 Update Bypass's update button in case a new working version is pushed.
A BIG thanks to @Nesterwork for tipping us off in the PSXHAX Shoutbox and @bodeg for the Chaitin Tech PS4 exploit patch confirmation news from @flatz!
Download: PS4 Firmware 4.06 Update (US) / PS4 Firmware 4.06 Update (EU) / PS4 Firmware 4.06 Update (UK) / PS4 Firmware 4.06 Update (AU/NZ) / PS4 Firmware 4.06 Update (JP)
Main features in system software update 4.06
- This system software update improves the quality of the system performance.
A BIG thanks to @Nesterwork for tipping us off in the PSXHAX Shoutbox and @bodeg for the Chaitin Tech PS4 exploit patch confirmation news from @flatz!