Refer to History for a tabular overview of all Weka releases.

Several branches are associated with the 1st, 2nd, 3rd, and 4th edition of the book Data Mining: Practical Machine Learning Tools and Techniques by Ian H. Witten and Eibe Frank, joined by Mark Hall for the 3rd edition and Chris Pal for the 4th edition.

Once created, non-development branches receive bug fixes, but no new features (classifiers, filters, etc.).

Version name Most recent base number Associated with book edition
Book 1st ed. version 3.0.x 1st edition
Old GUI version 3.2.x none
Book 2nd ed. version 3.4.x 2nd edition
Book 3rd ed. version 3.6.x 3rd edition
Book 4th ed. version 3.8.x 4th edition
Development version 3.9.x none

For contributions, you should always develop against the developer version.