In May we announced that we are ending support for the Safe Browsing protocol version 1 on December 1. These new APIs provide simpler and more efficient access to the same data. If you haven’t yet migrated off of the version 1 API, we encourage you to do so as soon as possible. After January 1, 2012, we will turn off the service completely, and all requests will return a 404 error. The new version 2 API and the lookup service will use significantly less bandwidth.”]
Source: https://security.googleblog.com/2011/11/reminder-safe-browsing-version-1-api.html