The OS X Yosemite 10.10.1 update is recommended for all Yosemite users. It improves the stability and compatibility of your Mac.
– Improves Wi-Fi reliability
– Improves reliability when connecting to a Microsoft Exchange server
– Improves reliability sending Mail messages when using certain email service providers
– Improves reliability when connecting to remote computers using Back to My Mac
For more detailed information about this update, please visit: http://support.apple.com/kb/HT6572