I cannot state a clear month and year Mauser stopped exporting during WWI. As far as production, specifically of the pocket models it is clear that the majority, if not all of the .32 caliber pocket models were Imperially accepted (went to the German armed forces). Production of the .25 caliber model was greatly reduced and may of even stopped at some point during WWI. This may be why there appears to be a gap in .25 caliber serial numbers that would have been used during the war years. This occurs in the 1910/14 new model variation.
Regards,