The reserved folders have changed names:

Beta 1 Name	Beta 2 Name
Code	App_Code
Data	App_Data
Resources	App_GlobalResources
Themes	App_Themes
LocalResources	App_LocalResources
Browsers	App_Browsers

• The DataSetDataSource control has been removed.
• Connection strings can point to SQLExpress databases in the App_Data directory using a special syntax:

  Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|pubs.mdf;
                      Integrated Security=True;User Instance=True

  The |DataDirectory| is a special keyword and will be replaced with the actual path at runtime.

• The Access membership provider has been removed. Instead the Sql Server Membership Provider can be used, connecting to a local copy of SQLExpress, a cut-down version of SQL Server 2005 and the replacement for MSDE. SQLExpress supports automatic attachment of databases, so no configuration scripts are required; a database is copied into the App_Data directory as soon as you start using the membership provider.
• The Profile tab has been removed from the Web Site Administration Tool.

The Access personalization provider has been removed. Instead the Sql Server Membership Provider can be used, connecting to a local copy of SQLExpress, a cut-down version of SQL Server 2005 and the replacement for MSDE. SQLExpress supports automatic attachment of databases, so no configuration scripts are required; a database is copied into the App_Data directory as soon as you start using the personalization provider.

The WebPartPageMenu has been removed. In its place you can manually code buttons or links, or use a list, such as shown below:

            <asp:DropDownList ID="WebPartMenu" runat="server"
                            AutoPostBack="true"
                            OnSelectedIndexChanged="MenuChanged">
                <asp:ListItem value="EditDisplayMode"
                            Text="Personalize the page" />
                <asp:ListItem value="BrowseDisplayMode" 
                            Text="Browse the page" Selected="true" />
                <asp:ListItem value="CatalogDisplayMode"
                            Text="Show Catalog" />
            </asp:DropDownList>

            <script runat="server">
                Sub MenuChanged(ByVal sender As Object, ByVal e As EventArgs)
                    Select Case WebPartMenu.SelectedValue
                        Case "EditDisplayMode"
                            Me.PartManager.DisplayMode = _
                                WebParts.WebPartManager.EditDisplayMode
                        Case "BrowseDisplayMode"
                            Me.PartManager.DisplayMode = _
                                WebParts.WebPartManager.BrowseDisplayMode
                        Case "CatalogDisplayMode"
                            Me.PartManager.DisplayMode = _
                                WebParts.WebPartManager.CatalogDisplayMode
                    End Select
                End Sub
            </script>
        

• The SiteCounters framework has been removed.
• GetCallbackEventReference has been moved into the ClientScript class to bring it in line with other client script features.
• Using explicit expressions for localization has changed, now requiring only two arguments. THe DefaultDesignerValue has been removed.

• The Device Adapter architecture has been removed, with the Mobile Tools being the recommended way to construct sites requiring access from mobile devices. Controls associated with the Device Adapter architecture, such as the ContentPager and PhoneLink have also been removed.
• The ConfigurationSettings class has been renamed to ConfigurationManager.
• The DynamicImage control has been removed. Shanku supplied a sample HttpHandler to replace it in his blog post.

The Configuration class has been renamed toWebConfigurationManager, the GetWebConfiguration method has been renamed to OpenWebConfiguration and the Update method has been renamed to Save.