Here's an oddity. I use claws-mail and the ManageSieve plugin on two servers: mail.gandi.net, running "Dovecot Pigeonhole", and imap.ionos.co.uk, running "NEMESIS ManageSieved v27.0". I have no problems with the script editor on Gandi scripts, but on ionos trying to add rules gives an error when Checking the Syntax: "LF without preceding CR not allowed". Don't know if the Ionos server is being overly sensitive, or whether ManageSieve is using a wrong end-of-line convention.