With the release of Drupal 8 around the corner there will be limited support available for Drupal 6 moving on. If your business depends on your website this may be a good time to upgrade. You may be wondering why upgrade to Drupal 7 if Drupal 8 is available. This is because it will take module developers some time (years that is) to release Drupal 8 versions of their modules. So it may take up to two more years until all your favourite modules are available for Drupal 8. Here is a brief list of things to keep in mind if you are planning to upgrade your site to Drupal 7.
Full Back Up
Perform a full back up of the site before going for any upgrade. A full backup includes database, core drupal files, contributed and custom modules, file upload folders and directory/file permissions.
Upgrading site requires updating the site to latest release of current version. So before upgrading to drupal 7 the site must be updated to latest drupal 6 release. This minor update may include security fixes or other bug fixes.
Upgrade Contributed Modules
Contributed modules are important part of a site if core does not provide enough support to meet the requirements. In drupal 6 it is almost obvious due to fewer features than drupal 7. So before upgrading make sure that all contributed modules have drupal 7 version. If any contributed modules from drupal 6 are attached to drupal 7 core then using it is strongly recommended.
No Drupal 7 Version?
If you find out that some contributed modules have no drupal 7 version then try to see whether those become part of drupal 7 core or may be as submodule of a contributed module with different name or maybe you can accomplish the feature of this missing module from a combination of some contributed modules of drupal 7. If neither of those work then plan for converting the code to drupal 7 by writing as custom module.
Converting Custom Modules
Before going for converting the code of custom module to drupal 7, make sure whether you can accomplish this feature from any contributed module of drupal 7. There might be a possibility that you can find module which features almost same functionality as your custom module does if not exact. If not such case then plan for converting the code to drupal 7 version. Special attention is needed for drupal built-in function used such as hook when converting. There might be case that some drupal 6 functions are converted to several pieces in drupal 7 or renamed to different names or several functionalities are combined to one function.
"Migrate" module proved to be valuable for data migration. Pay special attention to taxonomy terms, entity references and fields to make sure they are migrated properly along with the nodes. For upgrading and migrating fields (cck in drupal 6), drupal 7 CCK module is strongly recommended.
For converting theme to drupal 7, special attention is needed for naming convention of template files and region. These are quite different in drupal 7 from drupal 6.
Make sure to secure settings file and to check the report section for any issues after upgrading. These two are very easy to miss. Check drupal core modules and make sure that all standard modules are enabled for fresh drupal. In a Drupal 6 to 7 upgrade, some modules that may not be engaged are: 'Dashboard', 'Contextual Links', 'Overlay', 'Field', 'File', 'Image' and 'Shortcut'.
Hope these tips are helpful and gets you off the ground for your drupal upgrade project. If your project is already underway, what other things did you find that are worth paying attention to? Feel free to leave a comment, I’d love to hear from you.