diff --git a/CHANGELOG.md b/CHANGELOG.md
index f33d3e1..7f576a2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased][unreleased]
 
+## [3.1.1] - 2022-04-12
+- Updated version number in `readme.txt`.
+
 ## [3.1.0] - 2022-04-11
 - Set payment failure reason and redirect Drop-in on refusal (resolves #2).
 - Only set `applePayMerchantValidationUrl` when certificate is configured.
@@ -123,7 +126,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## 1.0.0 - 2019-03-28
 - First release.
 
-[unreleased]: https://github.com/pronamic/wp-pronamic-pay-adyen/compare/3.1.0...HEAD
+[unreleased]: https://github.com/pronamic/wp-pronamic-pay-adyen/compare/3.1.1...HEAD
+[3.1.1]: https://github.com/pronamic/wp-pronamic-pay-adyen/compare/3.1.0...3.1.1
 [3.1.0]: https://github.com/pronamic/wp-pronamic-pay-adyen/compare/3.0.1...3.1.0
 [3.0.1]: https://github.com/pronamic/wp-pronamic-pay-adyen/compare/3.0.0...3.0.1
 [3.0.0]: https://github.com/pronamic/wp-pronamic-pay-adyen/compare/2.0.4...3.0.0
diff --git a/package.json b/package.json
index 778a47d..ed4d297 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "adyen",
-  "version": "3.1.0",
+  "version": "3.1.1",
   "description": "Adyen driver for the WordPress payment processing library.",
   "repository": {
     "type": "git",
diff --git a/pronamic-pay-adyen.php b/pronamic-pay-adyen.php
index 0d7e2e6..988c74d 100644
--- a/pronamic-pay-adyen.php
+++ b/pronamic-pay-adyen.php
@@ -4,7 +4,7 @@
  * Plugin URI: https://www.pronamic.eu/plugins/pronamic-pay-adyen/
  * Description: Extend the Pronamic Pay plugin with the Adyen gateway to receive payments with Adyen through a variety of WordPress plugins.
  *
- * Version: 3.1.0
+ * Version: 3.1.1
  * Requires at least: 4.7
  *
  * Author: Pronamic
diff --git a/readme.txt b/readme.txt
index c391ef0..02ccd95 100644
--- a/readme.txt
+++ b/readme.txt
@@ -4,6 +4,6 @@ Tags: pronamic, pay, adyen, add-on
 Requires at least: 4.7
 Tested up to: 5.1
 Requires PHP: 5.3
-Stable tag: 3.0.0
+Stable tag: 3.1.1
 
 Extend the Pronamic Pay plugin with the Adyen gateway to receive payments with Adyen through a variety of WordPress plugins.