Users searching for drm to pdf conversion are typically trying to recover specially secured PDF documents (.drm files from Drumlin) as standard PDF files, something that might not be entirely possible.
As far as we know, .drm files can only be viewed using Drumlin software and only by the intended user with proper credentials. Without these not only it is impossible to open, but also convert these documents back to the original PDF files.
Updated: October 30, 2023