diff --git a/CHANGELOG.md b/CHANGELOG.md
index b71af61..49d675d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 6.3.3 (2023-07-20)
+
+### Bug fixes
+
+In Shell mode, don't allow spaces in heredoc tokens.
+
 ## 6.3.2 (2023-03-20)
 
 ### Bug fixes
diff --git a/package.json b/package.json
index 4db7915..756968d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@codemirror/legacy-modes",
-  "version": "6.3.2",
+  "version": "6.3.3",
   "description": "Collection of ported legacy language modes for the CodeMirror code editor",
   "scripts": {
     "test": "cm-runtests",