Hi again, According to RFC4918 (June 2007) Adding a calendar resource could cause a lost-update so clients are advised to use on of the following scheme: 1) If lock is supported request a lock on and Unmapped URL 2) If lock is not supported use the header If-None-Match (RFC2616) As I see it using If-None-Match header is more flexible and requires less from both client and server. My question is then: Are there any added benefit from using a Lock on and Unmapped URL if the server supports locking or should I use If-None-Match header anyway? -- Hilsen/Regards Michael Rasmussen Get my public GnuPG keys: michael <at> rasmussen <dot> cc http://keyserver.veridis.com:11371/pks/lookup?op=get&search=0xD3C9A00E mir <at> datanom <dot> net http://keyserver.veridis.com:11371/pks/lookup?op=get&search=0xE501F51C mir <at> miras <dot> org http://keyserver.veridis.com:11371/pks/lookup?op=get&search=0xE3E80917 -------------------------------------------------------------- Use uniform input formats. - The Elements of Programming Style (Kernighan & Plaugher)