Version 2.1.20 of the UDUNITS package was released on December 20, 2010. This version is recommended for all users. The latest update can be downloaded at https://www.unidata.ucar.edu/downloads/udunits.
Version 2.1.20 incorporates the following changes:
- Added 'fahrenheit' as an alias for 'degrees fahrenheit'.
- Added hyperlinks from HTML documentation to XML files of the units database.