Nile

• Squeak3.9 - Released 8 Dec 2006.
• Code changes, but only bug fixes - Code has changed but only with bug fixes.
• MIT - The MIT license is like BSD without the advertising clause. As free as it gets, suitable for cross Smalltalk 100% reuse. The recommended license for Squeak since the 4.0 release.
• Not backwards compatible - Code has changed and breaks compatibility for sure.
• Beta - Useable but still not stable, probably has bugs.

• Only one class for collection-based streams (0 trait)
• Only one class for file-based streams (0 trait)
• Three new traits to put common behavior (6 traits in the core now)

http://damien.cassou.free.fr/documents/internship2007/nile/completehierarchy.pdf