So just a quick summary of the newest update:
The front page plays a new morse code, which translates to NCRA UNIT BST 314 7 EMRG MSG NEW YORK STAGE 7 WASHINGTON STAGE 7 LOS ANGELES STAGE 7 AUSTIN STAGE 7 CHICAGO STAGE 7 NEW ORLEAN STAGE 7 LAS VEGAS UNKNOWN MIAMI STAGE 7 DALLAS STAGE 7 DENVER STAGE 7 SAN DIEGO STAGE 7 SAN FRANCISCO STAGE 7 BOSTO-
Several people have suggested that NCRA means National Catastrophe Relief Auxilliary. To quote /u/Mr_Milenko's comment:
http://fallout.wikia.com/wiki/Germantown_Logs Shows: National Catastrophe Relief Auxiliary - Response Unit MD-478 so if we take NCRA UNIT BST 314 7 National Catastrophe Relief Auxiliary - Unit BST 314. MD, in this case probably refers to Maryland. So.. BST is Boston.
The stage 7 probably refers to Level 7 on International Nuclear and Radiological Event Scale (INES) see:
http://en.wikipedia.org/wiki/International_Nuclear_Event_Scale#Level_7:_Major_accident'
Taking these things into account, the message is probably telling us that the cities mentioned have been hit by nukes (the stage 7 event). In the message, it says LAS VEGAS UNKNOWN, probably due to Mr. House's efforts to defend Las Vegas.
At the end of the message, the name Boston is cut off, arguably indicating that Boston got hit by a nuke at this exact point in the message.
The audiofile is called longfellow-52939ac559777.mp3. Longfellow might refer to several things. For example, there is a Longfellow Bridge in Boston, connecting Boston to Cambridge (where the Institute is situated). The bridge, in turn, is named after Henry Wadsworth Longfellow, a poet who died in Cambridge, Massachusetts (Here's a picture /u/volx1337 posted that shows the locations of the bridge and the Institute).
I believe that all the messages on the website are describing events prior to the war, and events happening during the war, as I explain in this comment. I think the newest update really reinforces this idea, as this message describes several cities being hit, and then Boston being hit. This fits well with yesterdays update, when the translated message stated Bridgeport, this is Concord (MA), message: Quabbin Reservoir is hit, repeat, Quabbin Reservoir is hit.
Maybe the messages are supposed to be in real-time from the Great War, but it could also be the case that the messages are recovered after the War.
I also really like the idea that /u/MadMaxGamer proposed in this comment:
What is Fallout 4 starts right as the bombs fall with you and everyone else scrambling to to get in the vault where you are put in suspended animation (frozen) along with others. They die, you survive. You are the survivor. Remember how Fallout 3 started with you as a kid ? Maybe this game has some gameplay before the bombs fall, before you are released into the wasteland. Just a thought...
How awesome would it be if, in Fallout 4, you kind of see yourself getting born just as in Fallout 3. Then at a few points, the game fast forwards a few years, showing you shreds of your life in the society just before the Great War. Suddenly, the air-raid sirens start to blare, and you and your family rush to the nearest Vault, where you are put in suspended animation, and when you wake up in 2299, you're the only survivor in the Vault!