I'm not sure when the transition happened, but when I asked them for information about my Doxa, they said their archives were flooded and all the documentation was destroyed.

Since your serial number falls between those two numbers, you know that your watch was made in 1917 or 1918. Looking at the table of Waltham serial numbers (see example below), you can see that number 20,900,000 was made in 1917 and 21,800,000 was made in 1918 (marked in red in the table below). It has a serial number on the back that starts in 54 would this be from 54 i could not find much on the serial numbers from a. Once we have received and processed your repair request, we will assign you an RMA number, and advise the service centre where we will be able to assist. The history of these pre-diver Doxas is quite blurry as the current Doxa company doesn't have many ties to the old Doxas except for the name. What I figured on was that, although small by today's standards (34mm), it wears large as the lug-to-lug distance is quite large.

Doxa Serial Numbers