DOCS-13914 update 4.0.21 changelog

Author: andf-mongodb

config/build_conf.yaml

@@ -10,7 +10,7 @@ project:
   branched: true
   siteroot: true
 version:
-  release: '4.0.20'
+  release: '4.0.21'
   branch: '4.0'
 system:
   files:

source/includes/changelogs/releases/4.0.21.rst

@@ -42,7 +42,8 @@ Query
 - :issue:`SERVER-39392` Invariant in PlanStage::dispose always evaluates as true
 - :issue:`SERVER-45233` Indexed inequalities to arrays return incorrect results
 - :issue:`SERVER-50291` Add query knob to enumerate $or children in a different order
-- :issue:`SERVER-51120` Find queries with MERGE_SORT incorrectly sort the results when the collation is specified 
+- :issue:`SERVER-51083` Problem with regex index bounds
+- :issue:`SERVER-51120` Find queries with SORT_MERGE incorrectly sort the results when the collation is specified 
 
 Aggregation
 ~~~~~~~~~~~
@@ -86,6 +87,8 @@ Internals
 - :issue:`SERVER-50736` Make OpenSSL explicitly accept SNIs presented in ClientHello
 - :issue:`SERVER-50818` Coverity analysis defect 114987: Wrapper object use after free
 - :issue:`SERVER-51106` Make the isMaster command a derived class of hello
+- :issue:`SERVER-51608` [4.0] backport implicitly_retry_on_background_op_in_progress.js
+- :issue:`SERVER-51802` Add requires_majority_read_concern tag to decrypt_tool.js on v4.0
 - :issue:`TOOLS-2589` [v4.0] sslAllowInvalidHostnames bypass ssl/tls server certification validation entirely
 - :issue:`WT-6421` Avoid parsing metadata checkpoint for clean files
 - :issue:`WT-6559` Use the session id from the new session to determine statistics bucket

source/release-notes/4.0.txt

@@ -15,8 +15,8 @@ Minor Releases
 
 .. _4.0.21-release-notes:
 
-4.0.21 - Upcoming
-~~~~~~~~~~~~~~~~~
+4.0.21 - Nov 10, 2020
+~~~~~~~~~~~~~~~~~~~~~
 
 Issues fixed: