Previous releases of Blender are available at download.blender.org/release

There you will also find:

  • The first 1.0 Irix Blender version
  • Blender 1.60, 1.73, 1.80, 2.04, 2.25
  • The 2.04 iPaq port.
  • The last BeOS port, Blender 2.11
  • Web plugin players

On the Past Releases page most recent previous release logs are available, with splash screens and list of features and improvements.

The source for all versions is available through the Blender code repositories, where you can browse source code files or see specific commits. See this page for all past versions tags.

Check also download.blender.org/source/chest/ for interesting source code from the past. it has old Blender versions as well as interesting in-house software from the company that developed Blender; dutch studio NeoGeo.