Release notes for Gerrit 2.9.3

Change-Id: I26e586c0ba94a743ec02a6ac4a5ff1be9efb119b
diff --git a/ReleaseNotes/ReleaseNotes-2.9.3.txt b/ReleaseNotes/ReleaseNotes-2.9.3.txt
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+Release notes for Gerrit 2.9.3
+==============================
+
+Download:
+link:https://gerrit-releases.storage.googleapis.com/gerrit-2.9.3.war[
+https://gerrit-releases.storage.googleapis.com/gerrit-2.9.3.war]
+
+Important Notes
+---------------
+
+*WARNING:* There are no schema changes from
+link:ReleaseNotes-2.9.2.html[2.9.2], but when upgrading from an existing site
+that was initialized with Gerrit version 2.6 to version 2.9.1 the primary key
+column order will be updated for some tables. It is therefore important to
+upgrade the site with the `init` program, rather than only copying the .war file
+over the existing one.
+
+It is recommended to run the `init` program in interactive mode. Warnings will
+be suppressed in batch mode.
+
+----
+  java -jar gerrit.war init -d site_path
+----
+
+Bug Fixes
+---------
+
+*Downgrade SSHD to 0.9.0-4-g5967cfd*
+
+In Gerrit version 2.9.2 SSHD was upgraded to 0.13.0 which included a fix for
+link:https://issues.apache.org/jira/browse/SSHD-348[SSHD-348 (SSH thread pool
+exhaustion)].
+
+It turned out that SSHD 0.13.0 still suffers from this issue, which causes
+problems for users of the stream-events in Gerrit 2.9.2.
+
+SSHD 0.9.0 is known to be free from this particular issue, but we cannot
+downgrade to that version because it includes some other known issues:
+
+* link:https://issues.apache.org/jira/browse/SSHD-254[SSHD-254 ('authenticated
+with partial success' error)]
+* link:https://issues.apache.org/jira/browse/SSHD-330[SSHD-330 (sporadic
+handshake failures)].
+
+SSHD version 0.9.0-4-g5967cfd is based on 0.9.0 and includes fixes for SSHD-254
+and SSHD-330.
+
+Due to the downgrade of SSHD, the following libraries are also downgraded:
+
+* Bouncycastle from 1.51 to 1.49
+* Mina Core from 2.0.8 to 2.0.7
diff --git a/ReleaseNotes/index.txt b/ReleaseNotes/index.txt
index 028d484..a28c715 100644
--- a/ReleaseNotes/index.txt
+++ b/ReleaseNotes/index.txt
@@ -4,6 +4,7 @@
 [[2_9]]
 Version 2.9.x
 -------------
+* link:ReleaseNotes-2.9.3.html[2.9.3]
 * link:ReleaseNotes-2.9.2.html[2.9.2]
 * link:ReleaseNotes-2.9.1.html[2.9.1]
 * link:ReleaseNotes-2.9.html[2.9]