Consider the following scenario:
You have a telephone that is running Microsoft Lync 2010 Phone Edition.
You deploy new updates to the telephone from the update server.
You restart the telephone, and then you select a language when you sign in to the telephone.
You enable high-contrast mode.
You try to enable high-contrast mode.
In this scenario, the high-contrast mode is not applied until you repower the telephone.
To resolve this issue, install the following cumulative update:
For Polycom CX500, Polycom CX600 and Polycom CX3000 telephones:
2577594 Description of the cumulative update for Lync 2010 Phone Edition for Polycom CX500, Polycom CX600, and Polycom CX3000: July 2011
For Aastra 6721ip and Aastra 6725ip telephones:
2577595 Description of the cumulative update for Lync 2010 Phone Edition for Aastra 6721ip and Aastra 6725ip: July 2011