when did it get upgraded?
July 2013
Boeing B-52 Stratofortress
In July 2013, the Air Force began a fleet-wide technological upgrade of its B-52 bombers called Combat Network Communications Technology (CONECT) to modernize electronics, communications technology, computing, and avionics on the flight deck. 
what is the 1994 fairchild air force base b-52 crash about? On Friday, 24 June 1994, a United States Air Force (USAF) Boeing B-52 Stratofortress crashed at Fairchild Air Force Base, Washington, United States who designed boeing b-52? Boeing engineers George S. Schairer, Art Carlsen and Vaughn Blumenthal
wiki:22151369
Boeing B-52 Stratofortress [SEP] Upgrades
Two bombers will have the ability to carry 40 weapons in place of the 36 that three B-52s can carry. The 1760 IWBU allows precision-guided missiles or bombs to be deployed from inside the weapons bay; previous aircraft carried these munitions externally on wing hardpoints. This increases the number of guided weapons (Joint Direct Attack Munition or JDAM) a B-52 can carry and reduces the need for guided bombs to be carried on the wings. The first phase will allow a B-52 to carry twenty-four GBU-38 500-pound guided bombs or twenty GBU-31 2,000-pound bombs, with later phases accommodating the JASSM and MALD family of missiles.