Fake News in Jewish Halacha

Jewish legal/ritual law is codified in the Halacha. Its roots are in the Written Law and the Oral Law. Can such a system provide up-to-date regulation for matters and concerns that did not exist 3000 years ago?

For example, the issue of "fake news".

The Shulchan Arukh (composed in the 16th century) at OH 222 stipulates that 

על שמועות שהן טובות לו לבדו מברך שהחיינו ואם הן טובות לו ולאחרים מברך הטוב והמטיב

when one hears good news that applies to himself alone, the blessing is the 'Shecheyanu' and if the news applies to others, the blessing is 'HaTov v'HaMeitiv".

And the Mishnah Brura (published in the 19th century) of the Chofetz Chaim adds:

 ודוקא כששמע מפי אדם נאמן וזה האדם ראה בעצמו אבל אם שמע שמועה [בין שמועה טובה שצריך לברך עליה הטוב והמטיב או שהחיינו בין שמועה רעה שצריך לברך עליה דיין האמת] ואין המגיד נאמן או שהמגיד לא ראה בעצמו לא יברך 

but only in the instance that he hears from a reliable person which is a person who saw it himself but if it is hearsay [either good or bad news which would affect the type of blessing to be said] and the person is unreliable or if the person relaying the news did not see it himself, he should not pronounce a blessing.

There it is. Don't go with "fake news".

And if you are told news, don't believe it until you can resource it reliably.

^