Enable sieve with LMTP.

installer.cfg

@@ -50,6 +50,8 @@ config_dir = /etc/dovecot
 user = vmail
 home_dir = /srv/vmail
 mailboxes_owner = vmail
+# Replace localhost with your domain
+postmaster_address = postmaster@localhost
 
 [nginx]
 enabled = true

modoboa_installer/scripts/dovecot.py

@@ -19,7 +19,8 @@ class Dovecot(base.Installer):
         "dovecot-sieve"
     ]
     config_files = [
-        "dovecot.conf", "dovecot-dict-sql.conf.ext", "conf.d/10-ssl.conf"]
+        "dovecot.conf", "dovecot-dict-sql.conf.ext", "conf.d/10-ssl.conf",
+        "20-lmtp.conf"]
     with_user = True
 
     def get_config_files(self):

modoboa_installer/scripts/files/dovecot/conf.d/20-lmtp.conf.tpl

@@ -0,0 +1,17 @@
+##
+## LMTP specific settings
+##
+
+# Support proxying to other LMTP/SMTP servers by performing passdb lookups.
+#lmtp_proxy = no
+
+# When recipient address includes the detail (e.g. user+detail), try to save
+# the mail to the detail mailbox. See also recipient_delimiter and
+# lda_mailbox_autocreate settings.
+#lmtp_save_to_detail_mailbox = no
+
+protocol lmtp {
+  postmaster_address = %postmaster_address
+  # Space separated list of plugins to load (default is global mail_plugins).
+  mail_plugins = $mail_plugins sieve
+}

modoboa_installer/scripts/files/dovecot/conf.d/20-managesieve.conf

@@ -27,7 +27,7 @@ service managesieve-login {
 
 service managesieve {
   # Max. number of ManageSieve processes (connections)
-  #process_count = 1024
+  #process_limit = 1024
 }
 
 # Service configuration