A few bugfixes and some useful features, namely:
Full list of bugs/features:
Rewrote the unit conversion logic to use CTools plugin. Now it is easier to provide a custom conversion logic and is more secure.
Fixing bugs and incorporating new features:
Slightly more mature version of Units module, now it is integrated with Features module (Units and Measures are exportable). Added the property 'symbol' to Units entities.
First reasonable try to port this module to Drupal 7.
Some great changes and implications:
Dev release for D7
No changes since last beta.
From now API is very simple. Code is very short and simple so there should not be any serious bugs.
Development snapshot.