diff --git a/PMJSON.podspec b/PMJSON.podspec
index 7766e26..24d987b 100644
--- a/PMJSON.podspec
+++ b/PMJSON.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name         = "PMJSON"
-  s.version      = "3.1.2"
+  s.version      = "4.0.0"
   s.summary      = "Pure Swift JSON encoding/decoding library"
   s.description  = "PMJSON provides a pure-Swift strongly-typed JSON encoder/decoder as well as a set of convenience methods for converting to/from Foundation objects and for decoding JSON structures."
 
diff --git a/README.md b/README.md
index 8557d59..36b1a90 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # PMJSON
 
-[![Version](https://img.shields.io/badge/version-v3.1.2-blue.svg)](https://github.com/postmates/PMJSON/releases/latest)
+[![Version](https://img.shields.io/badge/version-v4.0.0-blue.svg)](https://github.com/postmates/PMJSON/releases/latest)
 ![Platforms](https://img.shields.io/badge/platforms-ios%20%7C%20osx%20%7C%20watchos%20%7C%20tvos-lightgrey.svg)
 ![Languages](https://img.shields.io/badge/languages-swift-orange.svg)
 ![License](https://img.shields.io/badge/license-MIT%2FApache-blue.svg)
@@ -262,7 +262,7 @@ Unless you explicitly state otherwise, any contribution intentionally submitted
 
 ## Version History
 
-#### Development
+#### v4.0.0 (2019-11-14)
 
 * Update to Swift 5.
 * When encoding/decoding `URL`s with `JSON.Encoder` and `JSON.Decoder`, encode and decode their absolute string instead of relying on the native implementation which encodes them as an object. This matches the behavior of `JSONEncoder` and `JSONDecoder`.
diff --git a/Sources/Info.plist b/Sources/Info.plist
index b1376a8..1bcfa6d 100644
--- a/Sources/Info.plist
+++ b/Sources/Info.plist
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>3.1.2</string>
+	<string>4.0.0</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
diff --git a/Tests/PMJSONTests/Info.plist b/Tests/PMJSONTests/Info.plist
index f2f8ab7..18f6dd6 100644
--- a/Tests/PMJSONTests/Info.plist
+++ b/Tests/PMJSONTests/Info.plist
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>BNDL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>3.1.2</string>
+	<string>4.0.0</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>