Impressive.. There are many devs who are finding.. Bugs... But they are keeping it private.. Bug bounty program opened a backdoor for ps4 modding scene.. I am not going to update my ps4 anymore.. And i recommend you to. If you are interested in modding scene.. Oct0xor.. Received $40000 from sony. I think so he has found somthing more than a kernal exploit.. But who knows.. Lets wait and see.. We have only 1 bug which is public by theflow0.. And 90 bugs are total reported to sony right now.. Which means there are 89 more bugs which are private right now..(rumors) oct0xor found vurnabilties on ps4 blue ray dives!!
With the recent PS4 developments its certainly worth not updating your PS4 if your not actively playing online and want hacks. Lower firmware is always better as you can update, however can't downgrade.
Yes. If anyone have testkit\devkit (duhxxxx) they can downgrade.. But its not possible on retail console (cuhxxxx)