iPhone iOS 6.1.3 on 4s - repeated restarts

iOS failing in my case.

Since I updated last night, from my phone, it has cycled through at least a dozen involuntary restarts. I've noticed it while using it, and while it was idle. I've noticed it while charging and when detached. I've tried forcing restarts, and closing all running apps and restarting again. I see no pattern yet.

I saw nothing about issues on apple yet. So.... I will try to revert to 6.1.2 but not sure if I'm quick enough. It barely stays on long enough to check an email or type a five line text.

>>> Addendum, 27-March – Thank you all.
Other issues since updating:
-It seems this is an isolated matter since responders had no issues.
-Battery indicator gets stuck when charging, doesn’t show proper level.
-Battery life, talk time, standby otherwise seem okay for 22 months.
-Only happens after I reboot phone or cycle power off/on,
-Happens whether iPhone is charging or not.
-Looks like a power failure, screen fades, then shut down.
-Fewer involuntary restarts than day 0.