Thunderbird

• hide-local-folders : Pour masquer le dossier “Local Folders” quand on ne l'utilise pas, ou qu'on utilise que des comptes IMAP.
• Sieve : Sieve is a powerful script language for server-side mail filtering. It is intended to be used with IMAP and thus it is widely spread. Many IMAP Server are capable of running sieve filters. Sieve stores and runs all script on the server-side,
• imap-acl-extension : Extension to manage acls/permissions for shared mailboxes/folders on imap servers.

• https://github.com/spymastermatt/thunderbird-monterail/

Via : http://serverfault.com/questions/385187/dovecot-ignoring-maximum-number-of-imap-connections
Quand Thunderbird râle, du style Maximum number of connections from user+IP exceeded, augmenter le nombre de connexions du côté server avec Dovecot peut aider :

nano /etc/dovecot/dovecot.conf

protocol imap {
  mail_max_userip_connections = 50
}