This is a little more complicated than a simple upgrade.
Much of Content Construction Kit (CCK) in Drupal 6 is part of Drupal 7 core fields. Much but not all of CCK functionality is now part of Drupal 7 core. Several features require the installation of new, dedicated 7.x modules.
1. Download CCK and additional modules.
- http://drupal.org/project/references This project maintains the D7 versions of the 'Node reference' and 'User reference' field types, that were part of the CCK Package in D6.
- http://drupal.org/project/field_permissions Content permissions now require the Field Permissions module
- http://drupal.org/project/field_group Field Groups now requires the Field Group module.
- http://www.drupal.org/project/cck The latest CCK Module for 7.x
2. After completing the core upgrade, install CCK for 7.x
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Click Install new module, then browse for the module on your computer, and click install.
Repeat this procedure for all four modules.
3. Enable CCK and Content Migrate
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Put a check mark next to each one. Then expand the Fields section which will be lower on the page and put a checkmark next to each of those as well.
4. Enable the Fields module.
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When you've put check marks in all the boxes scroll to the very bottom of the page and click the Save Configuration button.
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To migrate the fields, go to Structure>Migrate fields and click on it. A new page will open with a list of fields to migrate. Click the checkbox next to each one you wish to migrate and click and be sure to save it when you are done.