The list goes like this:
Breaking Changes Overview
.NET Framework Version 2.0
- Threading Cancellation Functionality
- INullableValue Interface
- System.Nullable
- Boxing and Unboxing of Nullable
- MenuCommands Class
- Behavior Class
- ColumnWidthChangedEventArgs Class
- BindingContext Class
- DataGridViewRow Class
- DataGridViewCell Class
- Client Application User Settings
- Application Settings Serialization
- TreeView and TreeNode Classes
- BackgroundWorker Class
- MaskedTextBox Class
- GetPreferredSize Property of Form Controls
- Windows Forms API Changes
- CancelRowEdit Event
- AsyncCompletedEventArgs.Error Property
- RadioButton.TabStop Property
- MDI Automatic Merging
- BindingSource.Items Property
.NET Compact Framework
- EventArgs Classes
- XCertificateUI Class
- System.Threading.Thread Class
- KeyValuePair Class
- AssembliesVisibleTo Attribute
System.Data Namespace
Globalization
ClassVisual Studio Tools for Office
- VSTView Interface
Visual C++ Programming Language
- ATL Server — CAtlHttpClient Class
- Floating-point Control Word Support Functions
- Dynamic Cast from Private Base
- MFC Wrapper for LoadLibraryEx()
- MFC -bit Message Map Support
C# Programming Language
- Compilation Error Due to Implicit Conversion
- Checked and Unchecked Expressions
- Nullable
Does Not Satisfy IComparable Constraint Error - Cannot Form a Delegate Over Nullable
Error - Operator "is" Returns true for T and Non-null T?
Visual Basic Programming Language
- TypeOf Statement
- Non-CLS Compliant Return Types
- Overriding Object Members in Structures
- Namespaces with Different Casing
- Implementing MustOverride Methods
- AppActivate Case-insensitivity
- AppActivate Right-Hand Title
- CreateObject Case-insensitivity
- Zero-Based Collection Object
- FileIO Enumerations
- FileLogTraceListener.CustomLocation Property
- FileLogTraceListener Date Format
ClickOnce Runtime Process
- ClickOnce Store Change
- WebBrowser Permissions
Visual Studio
- Visual Studio Settings
- Machine.config File Changes
- Visual C++ Beta Project Open Error
- Errors When Deploying Device Projects to the Device Emulator
ASP.NET
- Unique Class Names
- HTML Default Validation Schema
- Events for Non-Visible Controls
- ICallbackEventHandler.GetCallbackResult Method
- ASP.NET Personalization Database Schema
- Page.CreateStateFormatter Method
- Aspnet_regiis.exe Utility Argument Change
- WebPart File Format
- System.Web.UI.IPageHeader
- Relative References in the Configuration File
- Web Project Global Settings and Project Policy Settings