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.
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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.