update CHANGELOG.md

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 [Semantic Versioning](https://semver.org/)
 
+## [1.9.1] - 2021-10-14
+### Bug fixes
+- More robust 'chain-mode' check in feature preset
+- Don't expand MP4 export controls as part of the symmetry preset
+
 ## [1.9.0] - 2021-09-29
 ### Added
 - Integrate PDBe/AlphaFold confidence coloring theme