A. Greger & Co., a bicycle manufacturer in Vienna, Austria, produced the Oliver No. 3 rebranded as the Courier. This machine was also produced as the Jacobi for a German office equipment dealer in Munich. The name "Jacobi" was taken from A. Greger and Company's sewing machine division. I know of only three Jacobi machines in existence. The second variation of the Courier is the Jwic, which was produced for the Czech market. I only know of two Jwic machines in existence.
When the backspacer was introduced on the Oliver No. 3 in 1912, A. Gregor and Co. added it to their machines as well. In 1914, A. Greger and Company updated their machines even more. The traditional olive green paint was discontinued in favor of black paint. The logo on the paper table for the Courier changed from displaying "Courier" to "The Courier Typewriter". The ribbon reverse and typebar covers were changed to the style of Oliver No. 5 machines.
The serial numbers for the Courier, Jacobi, and Jwic are intermixed. Based on known machines, I believe the first two digits of the serial number correspond to the year of manufacture. If this is correct, the running count reset each year, so less than 1000 machines were made per year. Since the earliest known Courier is 11488, this theory would indicate that production began in 1911. This theory also correlates to the introduction of the backspacer, which was introduced on the Oliver No. 5 in 1912. The earliest Courier/Jacobi/Jwic machine with a backspacer begins with "12" (12337). I have seen some sources claiming these machines were introduced in 1903, but I have yet to confirm this. It has also been said that production stopped in 1919 ending at serial number 19970, but this is incorrect; there is a Jacobi with serial number 20092. I believe machines were still being manufactured into 1920. Sources also claim these machines were still being assembled by 1924, and sold until 1927.