Polymer versions 0.5.3 and 0.5.4 released
Version 0.5.3 had a small dependency bug for Safari, this resulted in the rapid release of 0.5.4 to fix it.
Notable changes in the release are some paper-elements redesigned to adhere to the Material Design guideline.
The patch also had some fixes for some ShadowDOM polyfill issues in webcomponents.js.
For more info read the full release doc.