New in Mono 1.2.1
Core
Thread.Interrupt is finally implemented (Dick).

Many bug reports that were filed were fixed.

Web Services
Web Services now support generic types (List).

Web Services updates for the 2.0 API (Atsushi).

MIPS Port
Mono has been ported to the MIPS chip, port contributed by, this port is partial on the 1.2.1 release, to get a fully working version developers need to use SVN releases [Mark Mason].

Windows.Forms
Many bug fixes to Windows.Forms from the Winforms team, all the blocking bugs have been eliminated:

RichTextBox/TextBox received a lot of usability fixes, improved support for wrapping, performance enhancements and no longer crashes with long documents.
We pass all our unit tests on linux now (all 598 of them).
Transparent/translucent windows really work with Xgl + Compiz.
Startup performance improvements for X11 (use XInternAtoms instead of many XInternAtom calls).
Many more focus fixes.
Many, many TextBox/RichTextBox fixes.
NotifyIcon fixes (should work fine on linux now).
Popup windows (and menus) no longer steal focus from the main form on win32.
Fixed win32 bug which resulted in non-visible controls actually showing up at (0,0).
TreeView got its scrolling improved, expands and collapses without rendering glitches and rendering with ImageLists is fixed.
Datagrid fixes for handling DataSet binding/navigation.
X11 deadlock/hang/crash fixes for MT apps.
Printing UI is nicer (doesn't crash with unhandled exceptions) when you have no printers installed/configured.
Many toolbar/menu fixes.
System colors will keep their names, and track the Gtk names.
ComponentModel
Support for more type converters (arrays of strings were not previously supported), Sebastien.

ADO.NET
2.0 updates, XmlSchema reading and writing (Nagappan).

Process
The Process launching will now support opening special files in addition to launching programs. On FreeDesktop systems it will use xdg-open, if not, it will try to use gnome-open or kfmclient to open the files.

This means that Process.Start ("file.pdf") will open your PDF viewer, and Process.Start ("http://www.gnome.org") will launch your web browser to load that url.

System.Drawing and GDI+
Fixed UTF8 to UCS2 conversion [Choe Hwanjin]

Security
2.0 updates to X.509 certificates related classes.

ASP.NET 2.0
Many updates to the 2.0 stack from Mainsoft.

App_Code, App_LocalResources and App_GlobalResources, compilation support; Build providers for MasterPage, IgnoreFile, ForceCopy; from Marek Habersack.