iOS 12 is out now, but should you upgrade?
The short answer is "no" people.
It is explained in detail here though if you are interested as to why...
"Historically, almost every time Apple releases a major new software version, there are huge and gigantic bugs for some people that sometimes make your phone unusable for a few days until they fix the problem.
This isn’t to say that Apple’s quality is terrible: when you figure that there are a billion active iOS devices in use, even a problem that affects only 0.1% of situations is still going to cause problems for a million people. The fact that they don’t have more problems is quite remarkable."