Differences between broker61 and 65

Can any one give the differnces between broker 6.1 and 6.5

Hi all ,
till date we have used webmethods6.1 and we thought of to go with the new version of it .i mean webmethods6.5.
i tried to install it but,what i see is the license key which i had used for 6.1 is not supporting the 6.5.
can any one help me by giving me the license key for installation.
Awaiting response.

Contact your webMethods account rep for keys.

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