We have released version 2.18.5 of our JavaScript SDK, including several fixes and Unified Plan related changes, please take a look at the fixed issues (under "Fixed in previous versions" section):
https://tokbox.com/developer/sdks/js/release-notes.html#fixedIssues

and the release notes:
https://tokbox.com/developer/sdks/js/release-notes.html

For more information about Plan B deprecation and Unified Plan, please review this article.