Changes to Derwent WPI Update numbering and the total number of annual DWPI updates

As the total number of DWPI updates per year will move to 104 from 2020 onwards, the numbering format for fields /DW (DWPI Update, formerly known as Derwent Week), and /DUPD (DWPI Update, first and latest) has to be adjusted.

From the first update of DWPI in 2020, the format increased in length from 6-digits (YYYYWW) to 7-digits (YYYYWWW), where Y represents the year and W the update number.

The first 2020 update has DWPI Update 2020001, and can be searched with e.g. 2020001/DW. Pre-2020 updates in DWPI remain unchanged in their original 6-digit format.