The Canadian researchers claim to have deciphered the short-form code using a World War One artillery code book, reports the Daily Telegraph.
It is thought it was dispatched by Sergeant William Stott, 27, a paratrooper from the Lancashire Fusiliers who landed by parachute behind enemy lines on a special mission.
The message informed Royal Air Force officers that he was giving updates and he was also asking for information.
He died in action several weeks later. The researchers said some sections of the code still need to be cracked.