Here is imapsync 1.977 on host privremena, a linux system with 17.6/31.3 free GiB of RAM
with Perl 5.28.1 and Mail::IMAPClient 3.42
Transfer started at Wed Jul 29 14:23:24 2020
PID is 18370 my PPID is 18369
Log file is LOG_imapsync/2020_07_29_14_23_24_648_office@green-line.co.rs_tester@ranitovic.in.rs.txt ( to change it, use --logfile path ; or use --nolog to turn off logging )
Load is 0.34 0.30 0.35 1/1188 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 cp8.ulimitserver.com --host2 cp8.ulimitserver.com --password1 MASKED --password2 MASKED --user1 office@green-line.co.rs --user2 tester@ranitovic.in.rs
Temp directory is . ( to change it use --tmpdir dirpath )
Under cgi context
Umask set with 0077 (was 0022)
REMOTE_ADDR is ::ffff:89.216.99.93
HTTP_REFERER is http://148.251.112.220:8080/
HTTP_USER_AGENT is Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0
SERVER_SOFTWARE is ./webserver
SERVER_PORT is 8080
HTTP_COOKIE is imapsync_runs=4; 686c9b6492d74d6d7c41621a12c6956f=la6q3dnkojbe6vjjq7boesovf2
kill -QUIT 18370 # special behavior: call to sub catch_exit
kill -TERM 18370 # special behavior: call to sub catch_exit
kill -INT 18370 # special behavior: call to sub catch_reconnect
kill -HUP 18370 # special behavior: call to sub catch_print
kill -USR1 18370 # special behavior: call to sub toggle_sleep
File ./imapsync_cp8.ulimitserver.com_office@green-line.co.rs_cp8.ulimitserver.com_tester@ranitovic.in.rs.pid does not exist
Error reading file ./imapsync_cp8.ulimitserver.com_office@green-line.co.rs_cp8.ulimitserver.com_tester@ranitovic.in.rs.pid : No such file or directory
PID file is ./imapsync_cp8.ulimitserver.com_office@green-line.co.rs_cp8.ulimitserver.com_tester@ranitovic.in.rs.pid ( to change it, use --pidfile filepath ; to avoid it use --pidfile "" )
Writing my PID 18370 in ./imapsync_cp8.ulimitserver.com_office@green-line.co.rs_cp8.ulimitserver.com_tester@ranitovic.in.rs.pid
Writing also my logfile name in ./imapsync_cp8.ulimitserver.com_office@green-line.co.rs_cp8.ulimitserver.com_tester@ranitovic.in.rs.pid : LOG_imapsync/2020_07_29_14_23_24_648_office@green-line.co.rs_tester@ranitovic.in.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 [cp8.ulimitserver.com] port [993] user [office@green-line.co.rs]
Host2: IMAP server [cp8.ulimitserver.com] port [993] user [tester@ranitovic.in.rs]
Host1: connecting and login on host1 [cp8.ulimitserver.com] port [993] with user [office@green-line.co.rs]
Host1 IP address: 194.146.59.72
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: cp8.ulimitserver.com says it has CAPABILITY for AUTHENTICATE LOGIN
Host1: success login on [cp8.ulimitserver.com] with user [office@green-line.co.rs] auth [LOGIN]
Host2: connecting and login on host2 [cp8.ulimitserver.com] port [993] with user [tester@ranitovic.in.rs]
Host2 IP address: 194.146.59.72
Host2 banner: * OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE NAMESPACE LITERAL+ AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
Host2 capability before authentication: IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE NAMESPACE LITERAL+ AUTH=PLAIN AUTH=LOGIN AUTH
Host2: cp8.ulimitserver.com says it has CAPABILITY for AUTHENTICATE LOGIN
Host2: success login on [cp8.ulimitserver.com] with user [tester@ranitovic.in.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 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

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).


Host2: found quota, presented in raw IMAP
Sending: 5 GETQUOTAROOT INBOX
Sent 22 bytes
Read: 	* QUOTAROOT INBOX Mailbox "cPanel Account"
  	* QUOTA Mailbox (MESSAGE 12341 2147483647)
  	* QUOTA "cPanel Account" (STORAGE 0 52428800)
  	5 OK Getquotaroot completed (0.001 + 0.000 secs).

Host2: Quota current storage is 0 bytes. Limit is 53687091200 bytes. So 0.00 % full
Host1: found 6 folders.
Host2: found 7 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: [INBOX.]
Host2: prefix given by NAMESPACE: [INBOX.]
Host1: separator and prefix: [.][INBOX.]
Host2: separator and prefix: [.][INBOX.]
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.Archive        = \Archive
Host1: special INBOX.Trash          = \Trash
Host1: special INBOX.spam           = \Junk
Host1: special INBOX.Sent           = \Sent
Host1: special INBOX.Drafts         = \Drafts

Host2: special INBOX.Archive        = \Archive
Host2: special INBOX.Sent           = \Sent
Host2: special INBOX.spam           = \Junk
Host2: special INBOX.Trash          = \Trash
Host2: special INBOX.Drafts         = \Drafts


++++ 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 \Archive) "." INBOX.Archive
* LIST (\HasNoChildren \Trash) "." INBOX.Trash
* LIST (\HasNoChildren \Junk) "." INBOX.spam
* LIST (\HasNoChildren \Sent) "." INBOX.Sent
* LIST (\HasNoChildren \Drafts) "." INBOX.Drafts
16 OK List completed (0.001 + 0.000 secs).

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

Host2: folders list (first the raw imap format then the [X] = [Y]):
* LIST (\HasChildren) "." INBOX
* LIST (\HasNoChildren \Archive) "." INBOX.Archive
* LIST (\HasNoChildren \UnMarked \Sent) "." INBOX.Sent
* LIST (\HasNoChildren) "." INBOX.Junk
* LIST (\HasNoChildren \Junk) "." INBOX.spam
* LIST (\HasNoChildren \Trash) "." INBOX.Trash
* LIST (\HasNoChildren \Drafts) "." INBOX.Drafts
11 OK List completed (0.001 + 0.000 secs).

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

Folders in host2 not in host1:
[INBOX.Junk]

Folders mapping from --automap feature (use --f1f2 to override any mapping):
[INBOX.Trash]                            -> [INBOX.Trash]                           
[INBOX.spam]                             -> [INBOX.spam]                            
[INBOX.Drafts]                           -> [INBOX.Drafts]                          
[INBOX.Sent]                             -> [INBOX.Sent]                            
[INBOX.Archive]                          -> [INBOX.Archive]                         

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     1/6 [INBOX]                             Size: 3606018126 Messages: 12338 Biggest:  10176467
Host2 folder     1/6 [INBOX]                             Size: 3605929263 Messages: 12337 Biggest:  10176467
Host2-Host1                                                       -88863              -1                  0

Host1 folder     2/6 [INBOX.Archive]                     Size:         0 Messages:     0 Biggest:         0
Host2 folder     2/6 [INBOX.Archive]                     Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                            0               0                  0

Host1 folder     3/6 [INBOX.Drafts]                      Size:         0 Messages:     0 Biggest:         0
Host2 folder     3/6 [INBOX.Drafts]                      Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                            0               0                  0

Host1 folder     4/6 [INBOX.Sent]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     4/6 [INBOX.Sent]                        Size:      1688 Messages:     4 Biggest:       568
Host2-Host1                                                         1688               4                568

Host1 folder     5/6 [INBOX.Trash]                       Size:         0 Messages:     0 Biggest:         0
Host2 folder     5/6 [INBOX.Trash]                       Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                            0               0                  0

Host1 folder     6/6 [INBOX.spam]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     6/6 [INBOX.spam]                        Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                            0               0                  0

Host1 Nb folders:                     6 folders
Host2 Nb folders:                     6 folders

Host1 Nb messages:                12338 messages
Host2 Nb messages:                12341 messages

Host1 Total size:            3606018126 bytes (3.358 GiB)
Host2 Total size:            3605930951 bytes (3.358 GiB)

Host1 Biggest message:         10176467 bytes (9.705 MiB)
Host2 Biggest message:         10176467 bytes (9.705 MiB)

Time spent on sizing:         4.2 seconds
++++ Looping on each one of 6 folders to sync
ETA: Wed Jul 29 14:23:29 2020  0 s  12338/12338 msgs left
Folder     1/6 [INBOX]                             -> [INBOX]                            
Host1: folder [INBOX] has 12338 messages in total (mentioned by SELECT)
Host2: folder [INBOX] has 12337 messages in total (mentioned by SELECT)
Host2: folder [INBOX] permanentflags: 
Host1: folder [INBOX] considering 12338 messages
Host2: folder [INBOX] considering 12337 messages
Host1: folder [INBOX] selected 12338 messages, duplicates 3
Host2: folder [INBOX] selected 12337 messages, duplicates 0
ETA: Wed Jul 29 14:24:05 2020  0 s  0/12338 msgs left
Folder     2/6 [INBOX.Archive]                     -> [INBOX.Archive]                    
Host1: folder [INBOX.Archive] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.Archive]
ETA: Wed Jul 29 14:24:05 2020  0 s  0/12338 msgs left
Folder     3/6 [INBOX.Drafts]                      -> [INBOX.Drafts]                     
Host1: folder [INBOX.Drafts] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.Drafts]
ETA: Wed Jul 29 14:24:05 2020  0 s  0/12338 msgs left
Folder     4/6 [INBOX.Sent]                        -> [INBOX.Sent]                       
Host1: folder [INBOX.Sent] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.Sent]
ETA: Wed Jul 29 14:24:05 2020  0 s  0/12338 msgs left
Folder     5/6 [INBOX.Trash]                       -> [INBOX.Trash]                      
Host1: folder [INBOX.Trash] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.Trash]
ETA: Wed Jul 29 14:24:05 2020  0 s  0/12338 msgs left
Folder     6/6 [INBOX.spam]                        -> [INBOX.spam]                       
Host1: folder [INBOX.spam] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [INBOX.spam]
ETA: Wed Jul 29 14:24:05 2020  0 s  0/12338 msgs left
++++ End looping on each folder

Folders sizes after the synchronization.
You can remove this foldersizes listing by using  "--nofoldersizesatend"
Host1 folder     1/6 [INBOX]                             Size: 3606018126 Messages: 12338 Biggest:  10176467
Host2 folder     1/6 [INBOX]                             Size: 3605929263 Messages: 12337 Biggest:  10176467
Host2-Host1                                                       -88863              -1                  0

Host1 folder     2/6 [INBOX.Archive]                     Size:         0 Messages:     0 Biggest:         0
Host2 folder     2/6 [INBOX.Archive]                     Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                            0               0                  0

Host1 folder     3/6 [INBOX.Drafts]                      Size:         0 Messages:     0 Biggest:         0
Host2 folder     3/6 [INBOX.Drafts]                      Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                            0               0                  0

Host1 folder     4/6 [INBOX.Sent]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     4/6 [INBOX.Sent]                        Size:      1688 Messages:     4 Biggest:       568
Host2-Host1                                                         1688               4                568

Host1 folder     5/6 [INBOX.Trash]                       Size:         0 Messages:     0 Biggest:         0
Host2 folder     5/6 [INBOX.Trash]                       Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                            0               0                  0

Host1 folder     6/6 [INBOX.spam]                        Size:         0 Messages:     0 Biggest:         0
Host2 folder     6/6 [INBOX.spam]                        Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                            0               0                  0

Host1 Nb folders:                     6 folders
Host2 Nb folders:                     6 folders

Host1 Nb messages:                12338 messages
Host2 Nb messages:                12341 messages

Host1 Total size:            3606018126 bytes (3.358 GiB)
Host2 Total size:            3605930951 bytes (3.358 GiB)

Host1 Biggest message:         10176467 bytes (9.705 MiB)
Host2 Biggest message:         10176467 bytes (9.705 MiB)

Time spent on sizing:         3.3 seconds
++++ Statistics
Transfer started on                     : Wed Jul 29 14:23:24 2020
Transfer ended on                       : Wed Jul 29 14:24:08 2020
Transfer time                           : 44.1 sec
Folders synced                          : 6/6 synced
Messages transferred                    : 0 
Messages skipped                        : 12338
Messages found duplicate on host1       : 3
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    : 2 messages
Messages deleted on host1               : 0
Messages deleted on host2               : 0
Total bytes transferred                 : 0 (0.000 KiB)
Total bytes skipped                     : 3605826992 (3.358 GiB)
Message rate                            : 0.0 messages/s
Average bandwidth rate                  : 0.0 KiB/s
Reconnections to host1                  : 0
Reconnections to host2                  : 0
Memory consumption at the end           : 224.9 MiB (started with 159.9 MiB)
Load end is                             : 0.48 0.33 0.36 1/1186 on 2 cores
Biggest message                         : 0 bytes (0.000 KiB)
Memory/biggest message ratio            : NA
Start difference host2 - host1          : 3 messages, -87175 bytes (-85.132 KiB)
Final difference host2 - host1          : 3 messages, -87175 bytes (-85.132 KiB)
The sync looks good, all 12335 identified messages in host1 are on host2.
There is no unidentified message
The sync is not strict, there are 2 messages in host2 that are not on host1. Use --delete2 to delete them and have a strict sync. (12337 identified messages in host2)
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_07_29_14_23_24_648_office@green-line.co.rs_tester@ranitovic.in.rs.txt ( to change it, use --logfile filepath ; or use --nolog to turn off logging )
