The "E" in 7E7 stands for efficiency. And the last update was in 2002 for the Sonic Cruiser from Boeing. I think it's in the works but they just need to get past the issues of cost vs. speed. Thats where the Concorde lost out and was a business catastrophe. They're using a "cranked arrow" which has so little drag that plane can fly sub-sonic ( Mach .95-.98 ) and not waist fuel that the delta wing on the Concorde has which wastes a lot more fuel than this Sonic Cruiser concept. They might use the 777's engines if it's ever built. Here's a neat rendering
