diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5cf9b47..dee4871 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## [Unreleased]
 
+## v3.1.1 - 2024-08-31
+
 ### Fixed
 
 - Update type definition to add `cssNesting` constructor option ([#401](https://github.com/marp-team/marpit/pull/401))
diff --git a/package-lock.json b/package-lock.json
index 5dd5c68..48c324b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@marp-team/marpit",
-  "version": "3.1.0",
+  "version": "3.1.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@marp-team/marpit",
-      "version": "3.1.0",
+      "version": "3.1.1",
       "license": "MIT",
       "dependencies": {
         "@csstools/postcss-is-pseudo-class": "^5.0.0",
diff --git a/package.json b/package.json
index b59445e..821d0d3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@marp-team/marpit",
-  "version": "3.1.0",
+  "version": "3.1.1",
   "description": "The skinny framework for creating slide deck from Markdown",
   "license": "MIT",
   "author": {