Starting this month posuto uses Calendar Based versioning, so the latest release is `v2021.9.0`. The second component is the month; I wanted to use `09` but PyPI doesn't show leading zeroes so it'll just be like this. The final number is the release, it will be incremented if there's a bugfix or something.
Besides the versioning change there are no changes in functionality this month.
This month there were more updates than usual to normal postal codes.
- The artificial island [Choushuu Dejima](https://ja.wikipedia.org/wiki/%E9%95%B7%E5%B7%9E%E5%87%BA%E5%B3%B6) got a postal code (7510840)
- A [danchi in Tsukuba](https://www.city.tsukubamirai.lg.jp/page/page000174.html) got a new postal code (3002408)
- A [danchi in Kouchi Prefecture](https://www.pref.kochi.lg.jp/richi/park/nankoku-nissho/) got a new postal code (7830097)
- A number of postal codes in Yawata City in Kyoto with place names beginning with Matsui were removed (no news found) (6148292, 6148293, 6148291)
- Something seems to have changed with the organization of some codes in Imizu City in Toyama, though this may be a diff artefact (9390332, 9390333)