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2.6 Beta 2

Rating:        Based on 2 ratings
Reviewed:  1 review
Downloads: 5738
Released: Jul 23, 2009
Updated: Nov 10, 2009 by dfugate
Dev status: Beta Help Icon

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Release Notes

Note: this version of IronPython is for .NET Framework 2.0, 3.0 and 3.5. If you want a version of IronPython to work on .NET Framework 4.0 with C# 4.0's new "dynamic" keyword, you need a compatible version of IronPython. You can download IronPython for .NET Framework 4.0 Beta 1 from this site.

At this point we are essentially feature complete from a CPython 2.6 perspective, and look forward to making available IronPython 2.6 Release Candidate 1 within the next couple of months. As such, we’d very much like everyone to try out this release and report back any major problems you may encounter so we can fix them in time for the first release candidate. Any bugs that you find can be reported via

The primary focus of Beta 2 was bug fixing: a whopping 215 bugs were fixed in this release. The majority of these were fixes to standard CPython built-in modules with IronPython runtime fixes coming in at a close second. Some of the higher profile work items include:
  • The implementation of the sys module was improved so that you can now utilize CPython’s pdb module in basic scenarios to debug IronPython sessions provided you pass the –X:Frames or –X:FullFrames options to ipy.exe
  • 374 Implement _ctypes module
  • 20051 Re-raising exception causes loss of traceback
  • 18770 Support type inference on generic methods and improve function conversions - better LINQ support
  • 15399 'frame' object has no attribute 'f_back'
  • 17465 Implement rest of binascii module (package)
  • A bug was fixed in our build scripts that was leaving several working CPython standard modules out of our MSI installations. These included a few modules under the distutils package, two modules under encodings, code, codeop, and the io modules

A very visible new feature added to this release is that ipy.exe is now strictly a 32-bit only assembly. That is, it gets executed as a 32-bit CLR process on both x86 and x64 operating systems. ipy64.exe, despite what its name might imply, is a platform agnostic assembly matching the old behavior of ipy.exe in the sense that it gets executed as a 32-bit process on 32-bit OSes and 64-bit on 64-bit OSes. Why this change you ask? Quite simply put IronPython users with 64-bit OSes will see around a 33% improvement to IronPython startup time under ipy.exe!

Silverlight users: a new version of Silverlight, namely Silverlight 3.0, is required to build the “Silverlight Release” or “Silverlight Debug” configurations of IronPython.sln. Please update your Silverlight installation accordingly by visiting if you intend to build IronPython from sources.

Thanks to everyone in the IronPython Community who reported bugs and provided valuable feedback. We really do appreciate your input which helps to make every release of IronPython better than the last.

The IronPython Team

Reviews for this release

i like it! thanks! you guys!
by earthworm on Aug 24, 2009 at 2:34 AM