After upgrading to WP 3.5.1. Jetpack lost connection to wordpress.com - Unfortunately the Account @Wordpress.com was set up before my time of administration and it was only stored in jetpack.
This is a commercial Site and we need to have our stats for the last years back.
Of course i made a clean backup of the site before upgrading.
Any hints were I can find the original account jetpack used to connect to wordpress.com? :)