Case sensitive problem for vacation with dovecot lmtp pigeonhole

[kadafax at gmail.com]

Hi list,

This issue was raised here by John Fawcett on 12/02/19 but got no response.
So, as I'm facing the same issue, I would like to try again:

When using the vacation sieve extension, if I send an email to 
user.name at mydomain.com it will work, but not to User.Name at mydomain.com. 
Is there a way to make the user part case insensitive so that the 
vacation auto-reply is fired whatever the way user part is written ?

doveconf -n output:

# 2.3.5.1 (7ec6d0ade): /usr/local/etc/dovecot/dovecot.conf
# Pigeonhole version 0.5.5 (2483b085)
# OS: Linux 3.10.0-957.5.1.el7.x86_64 x86_64 CentOS Linux release 
7.6.1810 (Core)  ext4
# Hostname: myserver.mydomain.com
auth_master_user_separator = *
auth_username_chars = 
abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@*
auth_verbose = yes
debug_log_path = /var/log/dovecot-debug.log
default_client_limit = 10640
default_process_limit = 2128
default_vsz_limit = 0
hostname = mydomain.com
info_log_path = /var/log/dovecot.log
lda_mailbox_autocreate = yes
lda_mailbox_autosubscribe = yes
listen = *
log_path = /var/log/dovecot-error.log
login_greeting = Welcome
mail_gid = vmail
mail_location = maildir:/var/vmail/%Ln
mail_plugins = quota fts fts_lucene
mail_uid = vmail
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope 
encoded-character vacation subaddress comparator-i;ascii-numeric 
relational regex imap4flags copy include variables body enotify 
environment mailbox date index ihave duplicate mime foreverypart extracttext
namespace inbox {
   inbox = yes
   location = maildir:/var/vmail/%Ln
   mailbox Drafts {
     auto = subscribe
     special_use = \Drafts
   }
   mailbox Sent {
     auto = subscribe
     special_use = \Sent
   }
   mailbox "Sent Messages" {
     special_use = \Sent
   }
   mailbox Trash {
     auto = subscribe
     special_use = \Trash
   }
   prefix =
   type = private
}
passdb {
   args = /usr/local/etc/dovecot/deny-users
   deny = yes
   driver = passwd-file
}
passdb {
   args = /usr/local/etc/dovecot/master-users
   driver = passwd-file
   master = yes
   pass = yes
}
passdb {
   args = /usr/local/etc/dovecot/dovecot-ldap.conf.ext
   driver = ldap
}
plugin {
   fts = lucene
   fts_autoindex = yes
   fts_lucene = whitespace_chars=@.
   quota = maildir:User quota
   quota_rule = *:storage=30GB
   quota_rule2 = Trash:storage=+200M
   quota_warning = storage=95%% quota-warning 95 %u
   quota_warning2 = storage=80%% quota-warning 80 %u
   sieve = /var/sieve-scripts/%Ln.sieve
   sieve_dir = /var/vmail/%Ln/home/sieve
}
postmaster_address = postmaster at mydomain.com
protocols = imap pop3 lmtp sieve sieve
quota_full_tempfail = yes
service auth-worker {
   user = $default_internal_user
}
service auth {
   unix_listener /var/spool/postfix/private/auth {
     mode = 0777
     user = vmail
   }
}
service imap-login {
   inet_listener imaps {
     port = 993
     ssl = yes
   }
   process_min_avail = 10
}
service imap {
   process_limit = 2128
}
service lmtp {
   executable = lmtp -L
   process_min_avail = 15
   unix_listener /var/spool/postfix/private/dovecot-lmtp {
     group = postfix
     mode = 0600
     user = postfix
   }
}
service managesieve-login {
   inet_listener sieve {
     port = 4190
   }
}
service pop3-login {
   inet_listener pop3s {
     port = 995
     ssl = yes
   }
}
service quota-warning {
   executable = script /usr/local/bin/quota-warning.sh
   user = nobody
}
ssl_cert = </etc/letsencrypt/live/myserver.mydomain.com/fullchain.pem
ssl_dh = # hidden, use -P to show it
ssl_key = # hidden, use -P to show it
userdb {
   args = /usr/local/etc/dovecot/dovecot-ldap-userdb.conf.ext
   driver = ldap
   override_fields = uid=vmail gid=vmail home=/var/vmail/%Ln/home
}
protocol imap {
   mail_max_userip_connections = 30
   mail_plugins = quota fts fts_lucene imap_quota
}
protocol lmtp {
   info_log_path = /var/log/dovecot-lmtp.log
   log_path = /var/log/dovecot-lmtp-errors.log
   mail_plugins = quota fts fts_lucene sieve
}
protocol sieve {
   mail_max_userip_connections = 20
}