This is an expression which first began to be used in the 1940s by the U.S. Air Force test pilots.
When a pilot “pushes the envelope” he takes the plane beyond the recommended safety limits prescribed. He pushes the plane to the limits in order to determine what exactly the plane can do. The expression became popular thanks to a book by Tom Wolfe titled The Right Stuff.
Nowadays, the expression is used in everyday contexts to mean, “going beyond the limits” and “to stretch the boundaries”.
*The new company is beginning to push the envelope in the world of technology.