Here is imapsync 1.977 on host privremena, a linux system with 19.3/31.3 free GiB of RAM
with Perl 5.28.1 and Mail::IMAPClient 3.42
Transfer started at Fri Nov 13 22:01:01 2020
PID is 18837 my PPID is 18836
Log file is LOG_imapsync/2020_11_13_22_01_01_755_milan@mediadisplay.rs_milan@mediadisplay.rs.txt ( to change it, use --logfile path ; or use --nolog to turn off logging )
Load is 1.40 0.53 0.37 1/1197 on 2 cores
Current directory is /root/imapsync-master
Real user id is root (uid 0)
Effective user id is root (euid 0)
$RCSfile: imapsync,v $ $Revision: 1.977 $ $Date: 2019/12/23 20:18:02 $ 
Command line used, run by /usr/bin/perl:
./imapsync --addheader --automap --host1 cp1.ulimitserver.com --host2 194.146.57.11 --password1 MASKED --password2 MASKED --user1 milan@mediadisplay.rs --user2 milan@mediadisplay.rs
Temp directory is . ( to change it use --tmpdir dirpath )
Under cgi context
Umask set with 0077 (was 0022)
REMOTE_ADDR is ::ffff:178.218.170.45
HTTP_REFERER is http://148.251.112.220:8080/
HTTP_USER_AGENT is Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:82.0) Gecko/20100101 Firefox/82.0
SERVER_SOFTWARE is ./webserver
SERVER_PORT is 8080
HTTP_COOKIE is imapsync_runs=2; 686c9b6492d74d6d7c41621a12c6956f=la6q3dnkojbe6vjjq7boesovf2
kill -QUIT 18837 # special behavior: call to sub catch_exit
kill -TERM 18837 # special behavior: call to sub catch_exit
kill -INT 18837 # special behavior: call to sub catch_reconnect
kill -HUP 18837 # special behavior: call to sub catch_print
kill -USR1 18837 # special behavior: call to sub toggle_sleep
File ./imapsync_cp1.ulimitserver.com_milan@mediadisplay.rs_194.146.57.11_milan@mediadisplay.rs.pid does not exist
Error reading file ./imapsync_cp1.ulimitserver.com_milan@mediadisplay.rs_194.146.57.11_milan@mediadisplay.rs.pid : No such file or directory
PID file is ./imapsync_cp1.ulimitserver.com_milan@mediadisplay.rs_194.146.57.11_milan@mediadisplay.rs.pid ( to change it, use --pidfile filepath ; to avoid it use --pidfile "" )
Writing my PID 18837 in ./imapsync_cp1.ulimitserver.com_milan@mediadisplay.rs_194.146.57.11_milan@mediadisplay.rs.pid
Writing also my logfile name in ./imapsync_cp1.ulimitserver.com_milan@mediadisplay.rs_194.146.57.11_milan@mediadisplay.rs.pid : LOG_imapsync/2020_11_13_22_01_01_755_milan@mediadisplay.rs_milan@mediadisplay.rs.txt
Info: will resync flags for already transferred messages. Use --noresyncflags to not resync flags.
Host1: probing ssl on port 993 ( use --nosslcheck to avoid this ssl probe ) 
Host1: sslcheck detected open ssl port 993 so turning ssl on (use --nossl1 --notls1 to turn off SSL and TLS wizardry)
Host2: probing ssl on port 993 ( use --nosslcheck to avoid this ssl probe ) 
Host2: sslcheck detected open ssl port 993 so turning ssl on (use --nossl2 --notls2 to turn off SSL and TLS wizardry)
SSL debug mode level is --debugssl 1 (can be set from 0 meaning no debug to 4 meaning max debug)
Host1: SSL default mode is like --sslargs1 "SSL_verify_mode=0", meaning for host1 SSL_VERIFY_NONE, ie, do not check the certificate server.
Host1: Use --sslargs1 SSL_verify_mode=1 to have SSL_VERIFY_PEER, ie, check the certificate server of host1
Host2: SSL default mode is like --sslargs2 "SSL_verify_mode=0", meaning for host2 SSL_VERIFY_NONE, ie, do not check the certificate server.
Host2: Use --sslargs2 SSL_verify_mode=1 to have SSL_VERIFY_PEER, ie, check the certificate server of host2
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 server [cp1.ulimitserver.com] port [993] user [milan@mediadisplay.rs]
Host2: IMAP server [194.146.57.11] port [993] user [milan@mediadisplay.rs]
Host1: connecting and login on host1 [cp1.ulimitserver.com] port [993] with user [milan@mediadisplay.rs]
Host1 IP address: 194.146.59.65
Host1 banner: * OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE NAMESPACE LITERAL+ AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
Host1 capability before authentication: IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE NAMESPACE LITERAL+ AUTH=PLAIN AUTH=LOGIN AUTH
Host1: cp1.ulimitserver.com says it has CAPABILITY for AUTHENTICATE LOGIN
Host1: success login on [cp1.ulimitserver.com] with user [milan@mediadisplay.rs] auth [LOGIN]
Host2: connecting and login on host2 [194.146.57.11] port [993] with user [milan@mediadisplay.rs]
Host2 IP address: 194.146.57.11
Host2 banner: * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE AUTH=PLAIN AUTH=LOGIN AUTH=DIGEST-MD5 AUTH=CRAM-MD5] Dovecot (Ubuntu) ready.
Host2 capability before authentication: IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE AUTH=PLAIN AUTH=LOGIN AUTH=DIGEST-MD5 AUTH=CRAM-MD5 AUTH
Host2: 194.146.57.11 says it has CAPABILITY for AUTHENTICATE LOGIN
Host2: success login on [194.146.57.11] with user [milan@mediadisplay.rs] auth [LOGIN]
Host1: state Authenticated
Host2: state Authenticated
Host1 capability once authenticated: IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE SNIPPET=FUZZY PREVIEW=FUZZY STATUS=SIZE NAMESPACE LITERAL+ NOTIFY SPECIAL-USE COMPRESS=DEFLATE QUOTA THREAD I18NLEVEL CONTEXT SNIPPET PREVIEW STATUS COMPRESS
Host2 capability once authenticated: IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE THREAD I18NLEVEL CONTEXT

Host1: found ID capability. Sending/receiving ID, presented in raw IMAP for now.
In order to avoid sending/receiving ID, use option --noid
Sending: 4 ID ("name" "imapsync" "version" "1.977" "os" "linux" "vendor" "Gilles LAMIRAL" "support-url" "https://imapsync.lamiral.info/" "date" "23-Dec-2019 20:18:02 +0000" "side" "host1")
Sent 181 bytes
Read: 	* ID ("name" "Dovecot")
  	4 OK ID completed (0.001 + 0.000 secs).


Host2: found ID capability. Sending/receiving ID, presented in raw IMAP for now.
In order to avoid sending/receiving ID, use option --noid
Sending: 4 ID ("name" "imapsync" "version" "1.977" "os" "linux" "vendor" "Gilles LAMIRAL" "support-url" "https://imapsync.lamiral.info/" "date" "23-Dec-2019 20:18:02 +0000" "side" "host2")
Sent 181 bytes
Read: 	* ID ("name" "Dovecot")
  	4 OK ID completed (0.001 + 0.000 secs).

Host1: found 7 folders.
Host2: found 1 folders.
Host1: guessing separator from folder listing: [.]
Host1: separator given by NAMESPACE: [.]
Host2: guessing separator from folder listing: [/]
Host2: separator given by NAMESPACE: [.]
Host1: guessing prefix from folder listing: [INBOX.]
Host1: prefix given by NAMESPACE: [INBOX.]
Host2: guessing prefix from folder listing: []
Host2: prefix given by NAMESPACE: []
Host1: separator and prefix: [.][INBOX.]
Host2: separator and prefix: [.][]
Including all folders found by default. Use --subscribed or --folder or --folderrec or --include to select specific folders. Use --exclude to unselect specific folders.
Host1: Checking wanted folders exist. Use --nocheckfoldersexist to avoid this check (shared of public namespace targeted).
Host1: Checking wanted folders are selectable. Use --nocheckselectable to avoid this check.
Turned on automapping folders ( use --noautomap to turn off automapping )
Host1: special INBOX.Sent           = \Sent
Host1: special INBOX.spam           = \Junk
Host1: special INBOX.Trash          = \Trash
Host1: special INBOX.Drafts         = \Drafts
Host1: special INBOX.Archive        = \Archive


++++ Listing folders
All foldernames are presented between brackets like [X] where X is the foldername.
When a foldername contains non-ASCII characters it is presented in the form
[X] = [Y] where
X is the imap foldername you have to use in command line options and
Y is the utf8 output just printed for convenience, to recognize it.

Host1: folders list (first the raw imap format then the [X] = [Y]):
* LIST (\HasChildren) "." INBOX
* LIST (\HasNoChildren \Sent) "." INBOX.Sent
* LIST (\HasNoChildren) "." INBOX.Junk
* LIST (\HasNoChildren \Junk) "." INBOX.spam
* LIST (\HasNoChildren \Trash) "." INBOX.Trash
* LIST (\HasNoChildren \Drafts) "." INBOX.Drafts
* LIST (\HasNoChildren \Archive) "." INBOX.Archive
17 OK List completed (0.001 + 0.000 secs).

[INBOX]
[INBOX.Archive]
[INBOX.Drafts]
[INBOX.Junk]
[INBOX.Sent]
[INBOX.Trash]
[INBOX.spam]

Host2: folders list (first the raw imap format then the [X] = [Y]):
* LIST (\HasNoChildren) "." INBOX
10 OK List completed (0.001 + 0.000 secs).

[INBOX]

Host1: will not syncing empty folders on host1. Use --noskipemptyfolders to create them anyway on host2

Folders sizes before the synchronization.
You can remove foldersizes listings by using "--nofoldersizes" and "--nofoldersizesatend"
but then you will also lose the ETA (Estimation Time of Arrival) given after each message copy.
Host1 folder     1/7 [INBOX]                             Size:  11922365 Messages:     3 Biggest:  11805773
Host2 folder     1/7 [INBOX]                             Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                    -11922365              -3          -11805773

Host1 folder     2/7 [INBOX.Archive]                     Size:         0 Messages:     0 Biggest:         0
Host2 folder     2/7 [Archive]                            does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     3/7 [INBOX.Drafts]                      Size:         0 Messages:     0 Biggest:         0
Host2 folder     3/7 [Drafts]                             does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     4/7 [INBOX.Junk]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     4/7 [Junk]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     5/7 [INBOX.Sent]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     5/7 [Sent]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     6/7 [INBOX.Trash]                       Size:         0 Messages:     0 Biggest:         0
Host2 folder     6/7 [Trash]                              does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     7/7 [INBOX.spam]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     7/7 [spam]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 Nb folders:                     7 folders
Host2 Nb folders:                     7 folders

Host1 Nb messages:                    3 messages
Host2 Nb messages:                    0 messages

Host1 Total size:              11922365 bytes (11.370 MiB)
Host2 Total size:                     0 bytes (0.000 KiB)

Host1 Biggest message:         11805773 bytes (11.259 MiB)
Host2 Biggest message:                0 bytes (0.000 KiB)

Time spent on sizing:         2.7 seconds
++++ Looping on each one of 7 folders to sync
ETA: Fri Nov 13 22:01:04 2020  0 s  3/3 msgs left
Folder     1/7 [INBOX]                             -> [INBOX]                            
Host1: folder [INBOX] has 3 messages in total (mentioned by SELECT)
Host2: folder [INBOX] has 0 messages in total (mentioned by SELECT)
Host2: folder [INBOX] permanentflags: 
Host1: folder [INBOX] considering 3 messages
Host2: folder [INBOX] considering 0 messages
Host1: folder [INBOX] selected 3 messages, duplicates 0
Host2: folder [INBOX] selected 0 messages, duplicates 0
msg INBOX/1 {89739}           copied to INBOX/1          2.07 msgs/s  181.840 KiB/s 87.636 KiB copied ETA: Fri Nov 13 22:01:05 2020  1 s  2/3 msgs left
msg INBOX/2 {26853}           copied to INBOX/2          3.31 msgs/s  188.206 KiB/s 113.859 KiB copied ETA: Fri Nov 13 22:01:05 2020  0 s  1/3 msgs left
msg INBOX/3 {11805773}        copied to INBOX/3          1.02 msgs/s  3.869 MiB/s 11.370 MiB copied ETA: Fri Nov 13 22:01:07 2020  0 s  0/3 msgs left
ETA: Fri Nov 13 22:01:07 2020  0 s  0/3 msgs left
Folder     2/7 [INBOX.Archive]                     -> [Archive]                          
Host1: folder [INBOX.Archive] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.Archive]
ETA: Fri Nov 13 22:01:07 2020  0 s  0/3 msgs left
Folder     3/7 [INBOX.Drafts]                      -> [Drafts]                           
Host1: folder [INBOX.Drafts] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.Drafts]
ETA: Fri Nov 13 22:01:07 2020  0 s  0/3 msgs left
Folder     4/7 [INBOX.Junk]                        -> [Junk]                             
Host1: folder [INBOX.Junk] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.Junk]
ETA: Fri Nov 13 22:01:07 2020  0 s  0/3 msgs left
Folder     5/7 [INBOX.Sent]                        -> [Sent]                             
Host1: folder [INBOX.Sent] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.Sent]
ETA: Fri Nov 13 22:01:07 2020  0 s  0/3 msgs left
Folder     6/7 [INBOX.Trash]                       -> [Trash]                            
Host1: folder [INBOX.Trash] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.Trash]
ETA: Fri Nov 13 22:01:07 2020  0 s  0/3 msgs left
Folder     7/7 [INBOX.spam]                        -> [spam]                             
Host1: folder [INBOX.spam] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.spam]
ETA: Fri Nov 13 22:01:07 2020  0 s  0/3 msgs left
++++ End looping on each folder

Folders sizes after the synchronization.
You can remove this foldersizes listing by using  "--nofoldersizesatend"
Host1 folder     1/7 [INBOX]                             Size:  11922365 Messages:     3 Biggest:  11805773
Host2 folder     1/7 [INBOX]                             Size:  11922365 Messages:     3 Biggest:  11805773
Host2-Host1                                                            0               0                  0

Host1 folder     2/7 [INBOX.Archive]                     Size:         0 Messages:     0 Biggest:         0
Host2 folder     2/7 [Archive]                            does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     3/7 [INBOX.Drafts]                      Size:         0 Messages:     0 Biggest:         0
Host2 folder     3/7 [Drafts]                             does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     4/7 [INBOX.Junk]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     4/7 [Junk]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     5/7 [INBOX.Sent]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     5/7 [Sent]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     6/7 [INBOX.Trash]                       Size:         0 Messages:     0 Biggest:         0
Host2 folder     6/7 [Trash]                              does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     7/7 [INBOX.spam]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     7/7 [spam]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 Nb folders:                     7 folders
Host2 Nb folders:                     7 folders

Host1 Nb messages:                    3 messages
Host2 Nb messages:                    3 messages

Host1 Total size:              11922365 bytes (11.370 MiB)
Host2 Total size:              11922365 bytes (11.370 MiB)

Host1 Biggest message:         11805773 bytes (11.259 MiB)
Host2 Biggest message:         11805773 bytes (11.259 MiB)

Time spent on sizing:         0.5 seconds
++++ Statistics
Transfer started on                     : Fri Nov 13 22:01:01 2020
Transfer ended on                       : Fri Nov 13 22:01:08 2020
Transfer time                           : 6.3 sec
Folders synced                          : 7/7 synced
Messages transferred                    : 3 
Messages skipped                        : 0
Messages found duplicate on host1       : 0
Messages found duplicate on host2       : 0
Messages found crossduplicate on host2  : 0
Messages void (noheader) on host1       : 0  
Messages void (noheader) on host2       : 0
Messages found in host1 not in host2    : 0 messages
Messages found in host2 not in host1    : 0 messages
Messages deleted on host1               : 0
Messages deleted on host2               : 0
Total bytes transferred                 : 11922365 (11.370 MiB)
Total bytes skipped                     : 0 (0.000 KiB)
Message rate                            : 0.5 messages/s
Average bandwidth rate                  : 1835.8 KiB/s
Reconnections to host1                  : 0
Reconnections to host2                  : 0
Memory consumption at the end           : 201.6 MiB (started with 159.9 MiB)
Load end is                             : 1.45 0.55 0.38 1/1192 on 2 cores
Biggest message                         : 11805773 bytes (11.259 MiB)
Memory/biggest message ratio            : 17.9
Start difference host2 - host1          : -3 messages, -11922365 bytes (-11.370 MiB)
Final difference host2 - host1          : 0 messages, 0 bytes (0.000 KiB)
The sync looks good, all 3 identified messages in host1 are on host2.
There is no unidentified message
The sync is strict, all 3 identified messages in host2 are on host1.
Detected 0 errors

Check if a new imapsync release is available by adding --releasecheck
Homepage: https://imapsync.lamiral.info/
Exiting with return value 0 (EX_OK: successful termination) 0/20 nb_errors/max_errors
Log file is LOG_imapsync/2020_11_13_22_01_01_755_milan@mediadisplay.rs_milan@mediadisplay.rs.txt ( to change it, use --logfile filepath ; or use --nolog to turn off logging )
