Backdrop 1.23.0 includes the Entity Reference module. For existing sites that have upgraded from a previous version of Backdrop, this module can be enabled to use its new functionality. This can be done by visiting the modules page (admin/modules), and checking the box for Entity Reference.
Switching from Contrib to Core Entity Reference
If your site previously was using the contributed module version of Entity Reference module (available from GitHub), the old module will continue functioning on your site. However, due to differences between the core Entity Reference module and the contributed Entity Reference module, it is recommended that the old module be removed from your installation to prevent problems in the future.
You can identify if your site is running the old version of Entity Reference module by checking your site's code directories. If a directory exists at /modules/entityreference or /sites/*/modules/entityreference, then your site is running the old Entity Reference module. The new core Entity Reference module resides at /core/modules/entityreference and should not be changed.
The new core version of Entity Reference is identical to the previous contributed version and has no reduced functionality. You may switch to using the Core Entity Reference module by performing the following steps:
- Delete the directory containing the old module from your installation (usually
/modules/entityreference. - Visit the modules page in the Backdrop UI to let Backdrop pick up the new core module location within
/core/modules/entityreference. - Run update.php to have the new core module clean up its installation.
If you have never used the old contributed Entity Reference module, then no special steps are necessary. You may enable the new Entity Reference module at any time on your existing sites.
Compatibility with "Node Reference" or "Reference" Module
Two other contributed modules also provided referencing solutions, the References project (which included separate User Reference and Node Reference modules) and the Reference module. If your site is using either of those modules, they will continue to work as-is. You may decide to not enable the new core-provided Entity Reference module to avoid confusion of multiple different types of reference fields.
A contributed module to convert from these different types of references over to the core-provided entity reference is planned, but not yet available.
Taxonomy Term References
The core "Taxonomy" module also provides a "Term Reference" field. Future versions of Backdrop CMS may replace Term Reference fields with the new Entity Reference. In such a case, an upgrade path will be provided by core to convert the fields from one type to another.