diff --git a/README.md b/README.md
index 4ccb85e2..08f5374d 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-[![GH Actions Status](https://github.com/choderalab/openmmtools/workflows/CI/badge.svg)](https://github.com/choderalab/openmmtools/actions?query=branch%3Amaster)
+[![GH Actions Status](https://github.com/choderalab/openmmtools/workflows/CI/badge.svg)](https://github.com/choderalab/openmmtools/actions?query=branch%3Amain)
 [![Anaconda Badge](https://anaconda.org/omnia/openmmtools/badges/version.svg)](https://anaconda.org/omnia/openmmtools)
 [![Downloads Badge](https://anaconda.org/omnia/openmmtools/badges/downloads.svg)](https://anaconda.org/omnia/openmmtools/files)
 [![ReadTheDocs Badge](https://readthedocs.org/projects/openmmtools/badge/?version=master)](https://openmmtools.readthedocs.io/en/master/)
diff --git a/docs/releasehistory.rst b/docs/releasehistory.rst
index 353c517a..13329e3a 100644
--- a/docs/releasehistory.rst
+++ b/docs/releasehistory.rst
@@ -1,6 +1,14 @@
 Release History
 ***************
 
+0.21.2 - Bugfix release
+=======================
+
+Bugfixes
+--------
+- Fixed UnboundLocalError when using a string to specify platform in ``platform_supports_precision`` (`#551 <https://github.com/choderalab/openmmtools/pull/551>`_). 
+
+
 0.21.1 - Bugfix release
 =======================