diff --git a/data/conf/dovecot/dovecot.conf b/data/conf/dovecot/dovecot.conf
index fbdb112da..274b79442 100644
--- a/data/conf/dovecot/dovecot.conf
+++ b/data/conf/dovecot/dovecot.conf
@@ -199,7 +199,8 @@ plugin {
   sieve_plugins = sieve_imapsieve sieve_extprograms
   sieve_vacation_send_from_recipient = yes
   sieve_redirect_envelope_from = recipient
-  # Notifications are sent with the address of the mailbox (not :from or postmaster), so mail policies apply
+  # Notifications are sent with the address of the mailbox (not :from or postmaster), so mail policies apply;
+  # the old notify extension always sends as postmaster and is on by default, so sieve_extensions disables it
   sieve_notify_mailto_envelope_from = recipient
   # From elsewhere to Spam folder
   imapsieve_mailbox1_name = Junk
@@ -217,7 +218,7 @@ plugin {
   quota_warning2 = storage=80%% quota-warning 80 %u
   sieve_pipe_bin_dir = /usr/lib/dovecot/sieve
   sieve_global_extensions = +vnd.dovecot.pipe +vnd.dovecot.execute
-  sieve_extensions = +notify +imapflags +vacation-seconds +editheader
+  sieve_extensions = -notify +imapflags +vacation-seconds +editheader
   sieve_max_script_size = 1M
   sieve_max_redirects = 100
   sieve_max_actions = 101