The Edirom Project develops several tools for digital scholarly editions of musical works since 2003. It collaborates with several Complete Works projects like the Carl-Maria-von-Weber-Gesamtausgabe, the Reger-Werkausgabe (RWA) and the OPERA-project. In this project, MEI is used to align digital facsimiles of musical sources, to store a digital critical report with all the notable annotations of the project editor, and a rendering of CMN-based MEI encodings is currently under development. Edirom closely collaborates with MerMEId, which will be used to provide much wider access to the MEI header than Edirom’s core focus, both in the Editor tool and the brand new online version of the Edirom.