Thunderbird/Enterprise/Migration

Moved to https://developer.mozilla.org/en/Thunderbird/Deploying_Thunderbird_in_the_Enterprise/Upgrading_Thunderbird_in_the_Enterprise

This is draft of a Migration Guide intended to help large organizations (also referred to as "enterprises") that use Thunderbird to upgrade to Thunderbird version 3. This initial draft is a summary of the draft author's knowledge regarding auto-sync / offline settings (bug 562589) and Thunderbird 3 migration issues relevant to administrators (bug 562589#c7) (as of 2010/05/06).