diff --git a/CHANGELOG.md b/CHANGELOG.md
index f35f1722..fd561b7c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+#### 1.5.1 Maintenance Release
+
+- Update `$toMillis()` to allow more complete range of ISO 8601 compatible dates (issue #140)
+- Fix `$append()` so that it doesn't mutate the first argument (issue #139)
+
 #### 1.5.0 Milestone Release
 
 - Restructured the entire test suite to be implementation language agnostic (PR #122)
diff --git a/package.json b/package.json
index 021f72e3..2b47e007 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "jsonata",
-  "version": "1.5.0",
+  "version": "1.5.1",
   "description": "JSON query and transformation language",
   "module": "jsonata.js",
   "main": "jsonata-es5.js",