Apple today seeded build 14B23 of OS X 10.10.1 to developers, one week after seeding the first OS X 10.10.1 beta, build 14B17, and nearly a month after first releasing OS X Yosemite to the public.The new beta is available through the Software Update mechanism in the Mac App Store and through the Mac Dev Center.
While it is unclear what improvements the first update to OS X Yosemite will bring, there are several bugs in the operating system including a major Wi-Fi issue that has caused connection problems for a number of users.
Apple is asking developers to focus on Wi-Fi, Exchange accounts in Mail, and the Notification Center.
Apple Seeds Second Beta of OS X Yosemite 10.10.1 to Developers [Mac Blog]