These pages describe best practices for converting modules and themes from Drupal 7 to Backdrop CMS.
For projects built on other versions of Drupal (such as Drupal 6 or 8), it is recommended to convert these projects first to Drupal 7 before commencing conversion to Backdrop.
Before you begin
Before you jump into the code, we recommend you create two issues, one for the Backdrop community, and one for the Drupal community.
Communicating: Let everyone know you are working on a project
Create an issue in the drupal.org issue queue for the module or theme you are porting.
Here you can politely asking the current maintainer(s) if they are interested in supporting a Backdrop version, or porting the module themselves. You can offer to port the module, maintain the module, or co-maintain the module with them (or alone, if they are not interested). Please tag the issue with backdrop-port.
Creating an issue not only notifies the current module maintainers of what you are up to (it's their baby, after all), but it also helps other people working on Backdrop know not to duplicate work you are already doing, or to contact you if they would like to help you port the module, maintain a Backdrop version, or just test your work.
Create an issue in the Backdrop contrib group.
Here you can mention that a specific module is about to be ported, and link to the Drupal issue. This will allow anyone else working on Backdrop to collaborate with you on the port, rather than doing it again.
This post can also serve as an application to join the Backdrop Contrib group if you are not already a member.
The Change Records page documents API changes between Drupal 7 and Backdrop. If any unexpected errors or failures arise while attempting a module or theme or layout conversion these pages should be consulted. Most of the time this should lead to answers to resolve the problem; failing this, it is recommended to open an issue in the queue or ask in the forums.