Hi,
The autoupdate feature you're referring to is only available on the VPN3k, I'm not aware of a similar feature on an ISR router. The best way to update your users profiles would be to push down the new .pcf file to user's PCs through a third party tool such as Microsoft's Group Policy manager. Another idea for future supportability is to create a DNS name that resolves to your router and edit the .pcf file to use this dns name. This way in the future any ip address changes are invisible to users.
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