+* 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)