Although not supported in the first stable 1.1 version of mzIdentML, initial support for cross-linked peptide identification data was added in mzIdentML version 1.2. However, it has been determined that even mzIdentML 1.2 was underspecified for properly encoding some use cases in cross-linking data, e.g., when working with cleavable reagents. In addition, there is an effort underway as part of the PSI-PI working group to develop more extensive documentation and best-practice guidelines for encoding glycopeptides as well. Participation in this design process is actively sought.