Microsoft has released a new Office Insider Build. The new Build 12015.20004 brings improvements to PowerPoint, usual bug fixes and performance improvements. You can read the official changelog below.
Non-security updates:
Excel
We significantly improved the performance of deleting columns with merged cellsOffice Suite
We fixed an issue which could prevent some Unicode characters from being displayed when viewed in a browserOutlook
We fixed an issue which could have prevented files from being saved to a WebDAV locationPowerPoint
We fixed an issue where a user would click on one comment, but another comment would be selected