DOCSP-40400: whats new for v5.1.1 (#556)

* DOCSP-40400: whats new for v5.1.1

* staging

(cherry picked from commit 8d73f97)

Author: rustagir

source/whats-new.txt

@@ -19,6 +19,7 @@ What's New
 
 Learn what's new in:
 
+* :ref:`Version 5.1.1 <java-version-5.1.1>`
 * :ref:`Version 5.1 <version-5.1>`
 * :ref:`Version 5.0 <version-5.0>`
 * :ref:`Version 4.11 <version-4.11>`
@@ -36,6 +37,23 @@ Learn what's new in:
 * :ref:`Version 4.1 <version-4.1>`
 * :ref:`Version 4.0 <version-4.0>`
 
+.. _java-version-5.1.1:
+
+What's New in 5.1.1
+-------------------
+
+The 5.1.1 driver patch includes the following changes:
+
+- When using the ``MONGODB-OIDC`` authentication mechanism, you must not
+  include comma characters in the ``authMechanismProperties`` connection
+  string value. To learn more about this behavior, see the
+  :ref:`MONGODB-OIDC <mongodb-oidc>` section of the Enterprise
+  Authentication guide.
+
+- Optimizes GridFS throughput by removing redundant byte array cloning.
+  The ``GridFSDownloadStream`` and ``GridFSUploadStream`` types use
+  the ``BsonDocument`` type instead of ``Document``.
+
 .. _version-5.1:
 
 What's New in 5.1