In 1915, the German government requested 250,000 Model 4s. The Walther plant already was not able to produce enough M4s in 1915 and signed a license agreement with the Meffert, Suhl company. Meffert was also overwhelmed with this order and had manufactured with further subcontractors. Nine manufacturers were subcontracted to produce the Model 4 during WWI. A contract between Immanuel Meffert and the subcontractors dated 11/20/1916 stated that all subcontractors together have to produce 480 Walther model 4's weekly.
The serial numbers of these license pistols are between 60,000 to 100,000, and 130,000 to approximately 150,000.