The following features and fixes are available on the latest channel, and are candidates for the next stable release:
Changes
1.456.0: Improved loading and responsiveness across the editor for a faster, smoother experience. Text-editing toolbars also remain more stable and consistently positioned while editing or scrolling
1.457.0: Fixed images rendering with distorted proportions in Outlook 365
1.462.0: Fixed image dimension metadata causing distorted rendering in exported emails from API-created designs
1.477.0: Fix spacing issue with superscript text in email mode on mobile web browsers
Breaking changes
1.456.0: Lodash underscore variable is not available globally by default anymore, to reduce our bundle size; if you use it in your custom tools, include lodash as cdn separately, as seem here