While the rule is very much still in place and letters will be sent to any school attendee performing magic outwith the walls an old loophole is being used by some. As the muggeborns have seemed to rise in the world at a fast pace the purebloods have become worried. They need to defend themselves, they need to prepare their children. There is a reason that while they lose everything else they cling to their houses. Old magical homes have absorbed so much magic into their walls that children can be taught without without the trace being triggered.
Underage magic can be performed within the walls of an old magical house only without Ministry interference.
Shortly after the Battle of Hogwarts the Ministry passed laws protecting the rights of creatures. They could no longer be denied an education. Any employer not hiring just on the basis of crearture status would find himself with a hefty fine to pay. For a while it all seemed to be going to well. But, you can't change a peoples mind overnight. While The Ministry employed creatures (some would say to the extent they forgot humans) others did not. People were still afraid, still wary. This led to creatures reverting back to hiding what they were as best they could.
*** Most creatures had it written into law that they are responsible for teaching their own. Half-breeds tend to attend Hogwarts while full bloodied creatures do not.
This is now a mandatory class for all students in third year or above.
Wizarding Wireless Network
The wizarding world's main radio station now muggle music, radio drama's and once every day they will report on the muggle news.