diff --git a/CHANGELOG.md b/CHANGELOG.md
index ad5dfc1..56d05de 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,17 @@
+<a name="1.5.3"></a>
+## [1.5.3](https://github.com/showdownjs/showdown/compare/1.5.2...v1.5.3) (2016-12-19)
+
+
+### Bug Fixes
+
+* parser slowness with certain inputs ([da8fb53](https://github.com/showdownjs/showdown/commit/da8fb53)), closes [#315](https://github.com/showdownjs/showdown/issues/315)
+
+### Features
+
+* **requireSpaceBeforeHeadingText:** option to make space between `#` and header text mandatory ([5d19877](https://github.com/showdownjs/showdown/commit/5d19877)), closes [#277](https://github.com/showdownjs/showdown/issues/277)
+
+
+
 <a name="1.5.2"></a>
 ## [1.5.2](https://github.com/showdownjs/showdown/compare/1.5.1...1.5.2) (2016-12-17)
 
diff --git a/package.json b/package.json
index d5c124b..513907b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "showdown",
-  "version": "1.5.2",
+  "version": "1.5.3",
   "description": "A Markdown to HTML converter written in Javascript",
   "author": "Estevão Santos",
   "homepage": "http://showdownjs.github.io/showdown/",