This is definitely something which would be useful and we had considered. However, the MMCDA Document is a legal document which has specifications adopted by municipalities and incorporated into their bylaws. For this reason, all supplementaries are held seperate from the original document itself so that in referencing the specifications, if a municipality or district has not approved the supplementaries, the original specifications are not "missing" from the document.
To answer your question, the supplementaries must be printed out and incorporated and a city, municipality, company, etc. must decide which supplementaries to adopt. The MMCD makes every effort to notify members on our mailing list when new supplementaries are released.