Heres some news for those on PS4 Firmwares above:

Mathieulh has made a few statements in the past few days/weeks that are completely clear:
1) A group of hackers (himself at the very least) have access to kernel exploits (or better) that Sony havenít patched yet. Heís proven it by revealing some content from the 5.55 kernel a few days ago.
2) Thereís no planned release of any exploit for firmware 5.50 or above, that heís aware of. Again, given how spot-on heís been recently, thatís probably as good a prediction as youíre going to get for the time being.

Of course, nothingís impossible. My experience on the hacking scene tells me a PS4 exploit for 5.5x will happen eventually, but itís hard to tell ďwhenĒ. Given how recent the 5.05 exploit was, my personal opinion would be that people who want to jump on the hack bandwagon sooner than later should try and get a PS4 running 5.05. If those are getting too expensive for you, my second suggestion is: buy a second PS4, and keep one on a shelf until the firmware itís on gets hacked. Thatís what I did for 4.05 (it waited on a shelf for about 16 months).