From 1.x to 2.x
---------------
Upgrading from CDN integration 1.x to 2.x requires applying a new core patch.
The recommended steps to update your Drupal site are:
1) Copy the 1.x core patch (patches/drupal6.patch) to the Drupal root directory.
2) Revert the 1.x core patch:
    patch -p0 -R < drupal6.patch
3) Disable CDN integration at admin/settings/cdn.
4) Update the CDN integration module code.
5) Copy the 2.x core patch (patches/drupal6.patch) to the Drupal root directory.
6) Apply the 2.x core patch:
    patch -p0 < drupal6.patch
7) Re-enable CDN integration at admin/settings/cdn.

The ImageCache module patch has remained unchanged since version 1.x.