Here is imapsync 2.264 on host managebox.zxcs.nl, a linux system with 0.9/23.6 free GiB of RAM, 54.62% used by processes.
with Perl 5.16.3 and Mail::IMAPClient 3.37
Transfer started at Saturday 26 April 2025-04-26 04:10:29 +0200 CEST
PID is 71816 my PPID is 37675
Log file is 2025_04_26_04_10_29_325__.txt ( to change it, use --logfile path ; or use --nolog to turn off logging )
Load is 1.95 1.73 1.62 3/687 on 8 cores
Real user id is webimapsync (uid 1002)
Effective user id is webimapsync (euid 1002)
$RCSfile: imapsync,v $ $Revision: 2.264 $ $Date: 2023/10/17 11:09:25 $ 
Command line used, run by /usr/bin/perl:
/home/webimapsync/domains/imapsync.nl/cgi-bin/imapsync 
Under cgi context
Umask set with 0077 (was 0022)
REMOTE_ADDR is 127.0.0.1
HTTP_USER_AGENT is Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
SERVER_SOFTWARE is Apache/2.4.6 (CentOS) mod_perl/2.0.11 Perl/v5.16.3
SERVER_NAME is imapsync.nl
SERVER_ADDR is 127.0.0.1
SERVER_PORT is 80
SERVER_ADMIN is webmaster@imapsync.nl
Current directory is /var/tmp/imapsync_cgi/10f41bf28fe88eb447d975bbb5f45ded10493a2b
Temp directory is /var/tmp/imapsync_cgi/10f41bf28fe88eb447d975bbb5f45ded10493a2b ( to change it use --tmpdir dirpath )
Creating temp directory /var/tmp/imapsync_cgi/10f41bf28fe88eb447d975bbb5f45ded10493a2b
kill -QUIT 71816 # special behavior: call to sub catch_exit
kill -TERM 71816 # special behavior: call to sub catch_exit
kill -INT 71816 # special behavior: call to sub catch_reconnect
kill -HUP 71816 # special behavior: call to sub catch_print
kill -USR1 71816 # special behavior: call to sub toggle_sleep
File /var/tmp/imapsync_cgi/10f41bf28fe88eb447d975bbb5f45ded10493a2b/imapsync.pid does not exist
PID file is /var/tmp/imapsync_cgi/10f41bf28fe88eb447d975bbb5f45ded10493a2b/imapsync.pid ( to change it, use --pidfile filepath ; to avoid it use --pidfile "" )
Writing my PID 71816 in /var/tmp/imapsync_cgi/10f41bf28fe88eb447d975bbb5f45ded10493a2b/imapsync.pid
Writing also my logfile name in /var/tmp/imapsync_cgi/10f41bf28fe88eb447d975bbb5f45ded10493a2b/imapsync.pid : 2025_04_26_04_10_29_325__.txt
Info: will resync flags for already transferred messages. Use --noresyncflags to not resync flags.
Info: turned ON syncinternaldates, will set the internal dates (arrival dates) on host2 same as host1.
Host1: will try to use LOGIN authentication on host1
Host2: will try to use LOGIN authentication on host2
Host1: imap connection timeout is 120 seconds
Host2: imap connection timeout is 120 seconds
Host1: imap connection keepalive is on on host1. Use --nokeepalive1 to disable it.
Host2: imap connection keepalive is on on host2. Use --nokeepalive2 to disable it.
Under CGI context, a timeout can occur from the webserver, see https://imapsync.lamiral.info/INSTALL.d/INSTALL.OnlineUI.txt
Checking each --regexflag command with an space string.
Ok with each --regexflag
Exiting with return value 0 (EX_OK: successful termination) 0/500 nb_errors/max_errors PID 71816
Removing pidfile /var/tmp/imapsync_cgi/10f41bf28fe88eb447d975bbb5f45ded10493a2b/imapsync.pid
Log file is 2025_04_26_04_10_29_325__.txt ( to change it, use --logfile filepath ; or use --nolog to turn off logging )