diff --git a/CHANGELOG.md b/CHANGELOG.md
index 67c148b..7d8db19 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,10 +4,16 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 This CHANGELOG follows the format listed [here](https://github.com/sensu-plugins/community/blob/master/HOW_WE_CHANGELOG.md).
 
 ## [Unreleased]
-- check-postgres-replication.rb - critical if slave is undefined, localhost or master and slave are same
+
+## [4.0.0] - 2020-01-09
+
+### Breaking Changes
+- Update `sensu-plugin` dependency from `~> 1.2` to `~> 4.0` you can read the changelog entries for [4.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#400---2018-02-17), [3.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#300---2018-12-04), and [2.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#v200---2017-03-29)
+- `check-postgres-replication.rb`: both `--slave-host` and `master-host` arguments are now required flags where previously they had localhost defaults (@phumpal)
 
 ### Fixed
-- check-postgres-replication.rb: fix condition where connection timeout is considered a boolean rather than an integer value (@majormoses) (@phumpal) (@VeselaHouba)
+- `check-postgres-replication.rb`: fix condition where connection timeout is considered a boolean rather than an integer value (@majormoses) (@phumpal) (@VeselaHouba)
+- `check-postgres-replication.rb`: critical if the master and slave are same (@phumpal)
 
 ### Added
 - `check-postgres-query.rb`: Add `-r`, `--regex-pattern` to match query result against (@jindraj)
@@ -19,9 +25,6 @@ This CHANGELOG follows the format listed [here](https://github.com/sensu-plugins
 - Updated runtime dependency to 'pg' '1.2.1' from 1.1
 - Updated runtime dependency 'dentaku' '3.3.4' from 2.04
 
-### Breaking Changes
-- Update `sensu-plugin` dependency from `~> 1.2` to `~> 4.0` you can read the changelog entries for [4.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#400---2018-02-17), [3.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#300---2018-12-04), and [2.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#v200---2017-03-29)
-
 ## [3.0.0] - 2019-11-20
 ### Breaking Changes
 - Removed ruby < 2.4 since these Rubies are EOL (@phumpal)
@@ -203,7 +206,8 @@ This CHANGELOG follows the format listed [here](https://github.com/sensu-plugins
 ### Added
 - initial release
 
-[Unreleased]: https://github.com/sensu-plugins/sensu-plugins-postgres/compare/3.0.0...HEAD
+[Unreleased]: https://github.com/sensu-plugins/sensu-plugins-postgres/compare/4.0.0...HEAD
+[4.0.0]: https://github.com/sensu-plugins/sensu-plugins-postgres/compare/3.0.0...4.0.0
 [3.0.0]: https://github.com/sensu-plugins/sensu-plugins-postgres/compare/2.4.0...3.0.0
 [2.4.0]: https://github.com/sensu-plugins/sensu-plugins-postgres/compare/2.3.2...2.4.0
 [2.3.2]: https://github.com/sensu-plugins/sensu-plugins-postgres/compare/2.3.1...2.3.2
diff --git a/lib/sensu-plugins-postgres/version.rb b/lib/sensu-plugins-postgres/version.rb
index 73f4402..80874cd 100644
--- a/lib/sensu-plugins-postgres/version.rb
+++ b/lib/sensu-plugins-postgres/version.rb
@@ -2,7 +2,7 @@
 
 module SensuPluginsPostgres
   module Version
-    MAJOR = 3
+    MAJOR = 4
     MINOR = 0
     PATCH = 0