From soap.txt...
http://zimbra.svn.sourceforge.net/vi.../docs/soap.txt
flags = (u)nread, (f)lagged, has (a)ttachment, (r)eplied, (s)ent by me, for(w)arded, (d)raft, deleted (x), (n)otification sent
color = numeric; range 0-127; defaults to 0 if not present; client can display only 0-7