Hi gopal2k,
as for the webphone, unfortunately we think this technology is still not very mature and yet is not fully supported by some versions of Asterisk (better with version 13), and the browsers.
In general if you update QueueMetrics your configuration doesn't change and new features are not enabled by default, you have to add them manually, but you still get all the improvement and bug fixes, so keeping it updated is highy recommended.
Also, using the new agent's page doesn't force you to use the webphone.
Mirko