Same Flight on Thursday 23rd for me.....
If you look at :-
http://info.flightmapper.net/flight/Vir ... ways_VS_11You can work out the planes & schedule.
Me
Tue-Thu 13:05 Heathrow, London (LHR) 3 15:25 Logan, Boston (BOS) E
VS 11 Non-stop Airbus A340-600 (346) 7:20 Effective 2015-07-14
through 2015-07-23You
Tue-Sat 13:05 Heathrow, London (LHR) 3 15:25 Logan, Boston (BOS) E
VS 11 Non-stop Airbus A340-600 (346) 7:20
Effective 2015-07-24 through 2015-08-15
Mon,Sun 13:05 Heathrow, London (LHR) 3 15:25 Logan, Boston (BOS) E
VS 11 Non-stop Boeing 747-400 (744) 7:20 Effective 2015-07-26 through 2015-08-17
Your just unfortunate with the Schedule change.
Currently the 747 is flying Fri-Mon, but that seems to be changing to Monday & Sunday. This weekend is the last Fri-Mon 747s
At least that my interpretation.