It is always difficult to tell what is truth when original documents are missing and without knowing on what material others have based their writing.
As well Bruno Lange listed the "Doppeltaube" as "MZ.1".
Actually there have been two versions of each, the gondola-pusher and the Doppeltaube, that were given with the MZ-designation. Maybe one day, I can print something more extensive than what is to find until now.
The story in short:
• In January 1910 Albatros (Dr. Huth) bought a Farman biplane in France, that he lend and finaly sold to the Army in January 1911. This Albatros F.1
became the first German Army biplane - serial "B 1".
• In June/July 1911 Benno König won the "Deutsche Rundflug" in an improved version Albatros F.2
, that was taken over afterwards, including an additional order of 6 machines - serials "B 2-B 8".
• Already at the "Herbstflugwoche 1911" in September/October Albatros entered a new machine with star-pilot Alfred Pietschker. Pietschker won the competition and set up new world records in altitude and duration with two passengers. His pusher biplane later became known as Albatros Militär-Zweidecker
(before the term "Doppeldecker" became popular in Germany). This type again was orderd by the army in 11 copies. I have no verification, but I assume it was the winning machine and 10 additional copies.
• Early in 1912 Albatros brought out a new version of their pusher biplane with covered gondola, slightly smaller with revised tank installment, mainly two rudders only and other details. This would be the Albatros MZ.2
, of wich very little is to find unfortunately. You have to remind that there was a constant developement and several modifications, not a series production by any standards. Often there is written: "The Albatros MZ was built in several variants".
• A little later in 1911, Albatros developed the Doppeltaube
, one of the first real fuselage biplanes in Germany. The first time this type was presented to public was the Olympia Aero Show in London, December 1911. In April 1912 it was shown at the ALA in Berlin. It had a greater weight than the pushers, but showed more stable flight characteristics with the Taube-wings and offered a higher payload than other mono- and biplanes of the time.
• In mid 1912 a second version of the Doppeltaube followed. It got a more modern tailplane and three-bay wings (or three sets of V-struts sideways) and again had an increased weight and payload. This type sometimes is given as "Albatros MZ.2" as well, while I would prefer Albatros Doppeltaube 2
. In all 46 copies of both Albatros Doppeltauben were taken over by the army in 1912.
Well the Albatros Doppeltaube was a "Militär-Zweidecker" in the sence that it was a biplane that served with the army, and probably was advertised as this. Numerical differention was done some times later, I believe.
But in my eyes, to give the Doppeltaube as "Albatros MZ.1" is an unfortunate designation. First beacuse of the conflicting/douplicated designation, and second because the gondola-pusher definitely predated the Doppeltaube.
Edit: It is unlikely that both types were flown after 1913.