How to Download Older version of WordPress, BBPress and BuddyPress?

It is not easy to find the older version of the wordpress and it's projects from the download page. The code for the older version seems to be hosted on trac SVN of the each project. This applies to all the automattic projects like WordPress, buddypress, BBpress too.

You can go to respective trac SVN page of the project. e.g. BBPress has Trac Browser page listed here.

Click on branches folder and check specific version from the source tree. Select the folder and then look at the bottom of the page for the link " Download in other formats:  Zip Archive."

Click on the link and download the older version.

That's it. This same method applies to every wordpress and it's child projects.