Is it possible to downgrade PS Vita???

[GTA Tycoon 3]

Last day I was setting up my vita, while I was with henkaku active, when I saw that in update settings appeared two new things, the first one was update using storage media, and the second, using mtp.
Ok, at this point all was like always, but when I got into update using storage media, I saw that it was showing up a lower version, that was 3.15, the same version of the version when I bought the vita.
Ok, my question is that if I update to that "update 3.15", I'll get into that version?, or that will corrupt and brick my vita?
I'll show you some screenshots:

2016-09-07-090143.jpg

2016-09-07-090147.jpg

Thank you for helping me

[hackinformer]

No downgrading or anything like that..