Did the update this am. This is what it looks like on my phone.
The problem is the data connection and it seems to affect both 4G and Wi-Fi, so fixing wi-fi isn't going to help.
Some apps are affected, and some are not, even though they all use the data connection.
Google maps app, Google Play store, Weatherbug, etc all have problems.
Error message is: can't connect to server, network error, bad proxy configuration.
I've been using the Baidu web browser, and it seems to work okay, but most of the popular browsers are affected by this problem.
Otherwise, everything else seems to be okay. So far.
In any case, I think the problem is somewhere in the general communications software of the S4.
I'm hoping that others will check this theory out and verify which apps, which require data communications, still work, and which ones don't.
Also hoping that others will verify whether the problem affects both 4G and wi-fi.