[FAB-11756] Upgrade from v1.2 to v1.3 doc

Change-Id: I14ceabb8d1dd52e1f7db0ca0cfdf95025a5b564d
Signed-off-by: joe-alewine <Joe.Alewine@ibm.com>

Author: joe-alewine

docs/source/upgrade_to_newest_version.rst

@@ -1,18 +1,18 @@
 Upgrading to the Newest Version of Fabric
 =========================================
 
-At a high level, upgrading a Fabric network to v1.2 can be performed by following these
+At a high level, upgrading a Fabric network to v1.3 can be performed by following these
 steps:
 
  * Upgrade the binaries for the ordering service, the Fabric CA, and the peers.
    These upgrades may be done in parallel.
  * Upgrade client SDKs.
- * Enable the v1.2 capability.
+ * Enable the two v1.3 capabilities.
  * (Optional) Upgrade the Kafka cluster.
 
 To help understand this process, we've created the :doc:`upgrading_your_network_tutorial`
 tutorial that will take you through most of the major upgrade steps, including
-upgrading peers, orderers, as well as the capability. We've included both a
+upgrading peers, orderers, as well as the capabilities. We've included both a
 script as well as the individual steps to achieve these upgrades.
 
 Because our tutorial leverages the :doc:`build_network` (BYFN) sample, it has
@@ -21,7 +21,12 @@ included a section at the end of the tutorial that will show how to upgrade
 your CA, Kafka clusters, CouchDB, Zookeeper, vendored chaincode shims, and Node
 SDK clients.
 
-If you want to learn more about capability requirements, click `here <http://hyperledger-fabric.readthedocs.io/en/latest/capability_requirements.html>`_.
+If you want to learn more about capability requirements, check out the
+:doc:`capability_requirements` documentation.
+
+.. note:: With the removal of the old Event Hub in v1.3, please make sure to
+          update your applications to be compatible with the :doc:`peer_event_services`,
+          otherwise your applications may break after upgrade.
 
 .. Licensed under Creative Commons Attribution 4.0 International License
    https://creativecommons.org/licenses/by/4.0/