Apple has just seeded the very first beta of what will become the first update to the redesigned OS X Yosemite that was launched last month. The update to version 10.10.1 has a build number of 14B17.
The change notes indicate that Apple is making improvements in the areas of Wi-Fi connectivity, Exchange support in the Mail application, and the Notification Center, which gained support for widgets in the new operating system.
The beta can be downloaded through the Updates tab in the Mac App Store for users who have joined the AppleSeed pre-release program or developers running beta versions of OS X. It should also be available in the Mac Developer Center.