OS X Yosemite version 10.10.1 beta 2 is released by Apple to Developers. Registered Developers can download this OS X 10.10.1 Beta 2 Build 14B23, If you participated in Apple Public Beta program then you will be received an email from Apple about this Beta 2 update.
After installing OS X Yosemite, different people having problem with WiFi and some Mail related errors. Apple first released Beta 1 for OS X 10.10.1 that and now Beta 2 that asked developers to focus on the WiFi, Mail, Notification Center issues and may be some other bugs as well. This is not a very big update in size, OS X 10.10.1 Build 14B23 is around 300MB.
Release date for this update to public is unknown, so Join this Public Beta program now to get the beta version first If you are not a registered Mac Developer.