first draft

source/includes/language-compatibility-table-csharp.rst

@@ -45,6 +45,11 @@
      - .NET 4.7 [#2.14-note]_
      - .NET 4.6
 
+   * - 3.0
+     - ✓
+     - ✓
+     - 
+
    * - 2.13 to 2.30
      - ✓
      - ✓

source/upgrade/v3.txt

@@ -61,6 +61,17 @@ Version 3.0 Breaking Changes
   and {+mdb-server+} versions, visit the
   :ref:`Compatibility <csharp-compatibility-tables>` page.
 
+- The driver drops support for .NET Core 2.x and .NET Framework 4.6. You must upgrade to
+  .NET Core 3.x or later, or .NET Framework 4.7.2 or later.
+
+  To learn more about the compatibility between .NET/C# driver versions
+  and .NET versions, visit the
+  :ref:`Compatibility <csharp-compatibility-tables>` page.
+
+- The v1.x legacy API, which was deprecated in v2, has been removed. If the driver
+  provides a replacement for a deprecated API, the compiler
+  messages in v2.x will display it.
+
 - The classes, methods, and properties in the ``MongoDB.Driver.Core`` namespace that were
   deprecated in v{+last-version-2-number+} are marked ``internal``. If the driver
   provides a replacement for a deprecated class, method, or property, the compiler
@@ -155,6 +166,12 @@ Version 3.0 Breaking Changes
   authentication provider in your application's bootstrap code. To learn more about
   using AWS authentication with the {+driver-short+}, see :ref:`csharp-mongodb-aws`.
 
+- To use In-Use Encryption, you must add the ``MongoDB.Driver.Encryption`` package to
+  your project and register the encryption mechanism in your application's bootstrap code.
+  To learn more about using In-Use Encryption with the {+driver-short+}, see
+  :manual:`In-Use Encryption </core/security-in-use-encryption>` in the {+mdb-server+}
+  manual.
+
 - If you try to serialize or deserialize a floating-point
   ``Infinity`` or ``NaN`` value to an integral representation, the driver throws an
   ``OverflowException``. To learn more about floating-point ``Infinity`` and ``NaN``