diff --git a/docs/src/main/sphinx/release.rst b/docs/src/main/sphinx/release.rst
index 901a31edfe32..6882fefc331c 100644
--- a/docs/src/main/sphinx/release.rst
+++ b/docs/src/main/sphinx/release.rst
@@ -10,6 +10,7 @@ Release notes
 .. toctree::
     :maxdepth: 1
 
+    release/release-400
     release/release-399
     release/release-398
     release/release-397
diff --git a/docs/src/main/sphinx/release/release-400.md b/docs/src/main/sphinx/release/release-400.md
new file mode 100644
index 000000000000..3083e745f2a2
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+++ b/docs/src/main/sphinx/release/release-400.md
@@ -0,0 +1,52 @@
+# Release 400 (12 Oct 2022)
+
+## General
+
+* Add output buffer utilization to `EXPLAIN ANALYZE VERBOSE`. ({issue}`14396`)
+* Increase concurrency for large clusters. ({issue}`14395`)
+
+## BigQuery connector
+
+* Add support for [truncating tables](/sql/truncate). ({issue}`14494`)
+
+## Delta Lake connector
+
+* Prevent coordinator out-of-memory failure when querying a large number of
+  tables in a short period of time. ({issue}`14571`)
+
+## Hive connector
+
+* Reduce memory usage when scanning a large number of partitions, and add the
+  `hive.max-partitions-for-eager-load` configuration property to manage the
+  number of partitions that can be loaded into memory. ({issue}`14225`)
+* Increase the default value of the `hive.max-partitions-per-scan`
+  configuration property to `1000000` from `100000`. ({issue}`14225`)
+* Utilize the `hive.metastore.thrift.delete-files-on-drop` configuration
+  property when dropping partitions and tables. Previously, it was only used
+  when dropping tables. ({issue}`13545`)
+
+## Hudi connector
+
+* Hide Hive system schemas. ({issue}`14510`)
+
+## Iceberg connector
+
+* Prevent table corruption when changing a table fails due to an inability to
+  release the table lock from the Hive metastore. ({issue}`14386`)
+* Fix query failure when reading from a table with a leading double slash in the
+  metadata location. ({issue}`14299`)
+
+## Pinot connector
+
+* Add support for the Pinot proxy for controller/broker and server gRPC
+  requests. ({issue}`13015`)
+* Update minimum required version to 0.10.0. ({issue}`14090`)
+
+## SQL Server connector
+
+* Allow renaming column names containing special characters. ({issue}`14272`)
+
+## SPI
+
+* Add `ConnectorAccessControl.checkCanGrantExecuteFunctionPrivilege` overload
+  which must be implemented to allow views that use table functions. ({issue}`13944`)