Version 5Version 5 is not really a historical one.
But if you are interested in intermediate steps...
Well, here are the alpha versions that take us towards 5.0...
Download 5.0 alpha 007 (source code) - Lots of changes, started porting to a variety of platforms etc.
Download 5.0 alpha 007 (win32 precompiled)
Download 5.0 alpha 006 (source code) - Simple import/export mechanism to move classes from one image into another one
Download 5.0 alpha 006 (win32 precompiled)
Download 5.0 alpha 005 (source code) - Major enhancements like a Launcher/Transcript, a Workspace and a completely rewritten Class Browser
Download 5.0 alpha 005 (win32 precompiled)
Download 5.0 alpha004 - IUP2.5, CD4.4, SQLite 3.3.8, Visual C++ 2005 Express Edition
Download 5.0 alpha003 - Comes with the beginning of a foreign function interface (FFI)
Download 5.0_alpha002 - Some GUI extensions and some nice test code
Download 5.0_alpha001 - The beginning of the 5.0 odyssee... Has GUI and database support on a basic level.