Here is imapsync 1.977 on host privremena, a linux system with 12.5/31.3 free GiB of RAM
with Perl 5.28.1 and Mail::IMAPClient 3.42
Transfer started at Tue Nov 24 16:51:04 2020
PID is 5227 my PPID is 5226
Log file is LOG_imapsync/2020_11_24_16_51_04_523_profesionalni.kupci@mojatapeta.rs_profesionalni.kupci@mojatapeta.rs.txt ( to change it, use --logfile path ; or use --nolog to turn off logging )
Load is 1.56 1.82 1.81 4/1230 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 188.93.125.32 --host2 194.146.57.50 --password1 MASKED --password2 MASKED --user1 profesionalni.kupci@mojatapeta.rs --user2 profesionalni.kupci@mojatapeta.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:83.0) Gecko/20100101 Firefox/83.0
SERVER_SOFTWARE is ./webserver
SERVER_PORT is 8080
HTTP_COOKIE is imapsync_runs=13; 686c9b6492d74d6d7c41621a12c6956f=la6q3dnkojbe6vjjq7boesovf2
kill -QUIT 5227 # special behavior: call to sub catch_exit
kill -TERM 5227 # special behavior: call to sub catch_exit
kill -INT 5227 # special behavior: call to sub catch_reconnect
kill -HUP 5227 # special behavior: call to sub catch_print
kill -USR1 5227 # special behavior: call to sub toggle_sleep
File ./imapsync_188.93.125.32_profesionalni.kupci@mojatapeta.rs_194.146.57.50_profesionalni.kupci@mojatapeta.rs.pid does not exist
Error reading file ./imapsync_188.93.125.32_profesionalni.kupci@mojatapeta.rs_194.146.57.50_profesionalni.kupci@mojatapeta.rs.pid : No such file or directory
PID file is ./imapsync_188.93.125.32_profesionalni.kupci@mojatapeta.rs_194.146.57.50_profesionalni.kupci@mojatapeta.rs.pid ( to change it, use --pidfile filepath ; to avoid it use --pidfile "" )
Writing my PID 5227 in ./imapsync_188.93.125.32_profesionalni.kupci@mojatapeta.rs_194.146.57.50_profesionalni.kupci@mojatapeta.rs.pid
Writing also my logfile name in ./imapsync_188.93.125.32_profesionalni.kupci@mojatapeta.rs_194.146.57.50_profesionalni.kupci@mojatapeta.rs.pid : LOG_imapsync/2020_11_24_16_51_04_523_profesionalni.kupci@mojatapeta.rs_profesionalni.kupci@mojatapeta.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 did not detected open ssl port 993. Will use standard 143 port.
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)
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 [188.93.125.32] port [143] user [profesionalni.kupci@mojatapeta.rs]
Host2: IMAP server [194.146.57.50] port [993] user [profesionalni.kupci@mojatapeta.rs]
Host1: connecting and login on host1 [188.93.125.32] port [143] with user [profesionalni.kupci@mojatapeta.rs]
Host1 IP address: 188.93.125.32
Host1 banner: * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
Host1 capability before authentication: IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE AUTH=PLAIN AUTH=LOGIN AUTH
Host1: 188.93.125.32 says it has CAPABILITY for AUTHENTICATE LOGIN
Host1: success login on [188.93.125.32] with user [profesionalni.kupci@mojatapeta.rs] auth [LOGIN]
Host2: connecting and login on host2 [194.146.57.50] port [993] with user [profesionalni.kupci@mojatapeta.rs]
Host2 IP address: 194.146.57.50
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: 194.146.57.50 says it has CAPABILITY for AUTHENTICATE LOGIN
Host2: success login on [194.146.57.50] with user [profesionalni.kupci@mojatapeta.rs] auth [LOGIN]
Host1: state Authenticated
Host2: state Authenticated
Host1 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 SPECIAL-USE BINARY MOVE QUOTA THREAD I18NLEVEL CONTEXT
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.


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 2 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: []
Host1: prefix given by NAMESPACE: []
Host2: guessing prefix from folder listing: []
Host2: prefix given by NAMESPACE: []
Host1: separator and prefix: [.][]
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 )

++++ 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 (\HasNoChildren) "." Spam
* LIST (\HasNoChildren) "." INBOX
12 OK List completed.

[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     1/2 [INBOX]                             Size:   3629603 Messages:    19 Biggest:   1542272
Host2 folder     1/2 [INBOX]                             Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                     -3629603             -19           -1542272

Host1 folder     2/2 [Spam]                              Size:    269069 Messages:     5 Biggest:    182669
Host2 folder     2/2 [Spam]                               does not exist yet
Host2-Host1                                                      -269069              -5            -182669

Host1 Nb folders:                     2 folders
Host2 Nb folders:                     2 folders

Host1 Nb messages:                   24 messages
Host2 Nb messages:                    0 messages

Host1 Total size:               3898672 bytes (3.718 MiB)
Host2 Total size:                     0 bytes (0.000 KiB)

Host1 Biggest message:          1542272 bytes (1.471 MiB)
Host2 Biggest message:                0 bytes (0.000 KiB)

Time spent on sizing:         1.4 seconds
++++ Looping on each one of 2 folders to sync
ETA: Tue Nov 24 16:51:05 2020  0 s  24/24 msgs left
Folder     1/2 [INBOX]                             -> [INBOX]                            
Host1: folder [INBOX] has 19 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 19 messages
Host2: folder [INBOX] considering 0 messages
Host1: folder [INBOX] selected 19 messages, duplicates 0
Host2: folder [INBOX] selected 0 messages, duplicates 0
msg INBOX/1 {281015}          copied to INBOX/1          1.63 msgs/s  447.735 KiB/s 274.429 KiB copied ETA: Tue Nov 24 16:51:20 2020  14 s  23/24 msgs left
msg INBOX/2 {6534}            copied to INBOX/2          2.83 msgs/s  397.813 KiB/s 280.810 KiB copied ETA: Tue Nov 24 16:51:14 2020  8 s  22/24 msgs left
msg INBOX/3 {9889}            copied to INBOX/3          3.77 msgs/s  364.854 KiB/s 290.467 KiB copied ETA: Tue Nov 24 16:51:12 2020  6 s  21/24 msgs left
msg INBOX/4 {91911}           copied to INBOX/4          4.37 msgs/s  415.527 KiB/s 380.224 KiB copied ETA: Tue Nov 24 16:51:11 2020  5 s  20/24 msgs left
msg INBOX/5 {5917}            copied to INBOX/5          4.96 msgs/s  383.108 KiB/s 386.002 KiB copied ETA: Tue Nov 24 16:51:10 2020  4 s  19/24 msgs left
msg INBOX/6 {1428281}         copied to INBOX/6          4.48 msgs/s  1.299 MiB/s 1.739 MiB copied ETA: Tue Nov 24 16:51:11 2020  4 s  18/24 msgs left
msg INBOX/7 {34754}           copied to INBOX/7          4.80 msgs/s  1.215 MiB/s 1.772 MiB copied ETA: Tue Nov 24 16:51:10 2020  4 s  17/24 msgs left
msg INBOX/8 {10720}           copied to INBOX/8          5.15 msgs/s  1.148 MiB/s 1.782 MiB copied ETA: Tue Nov 24 16:51:10 2020  3 s  16/24 msgs left
msg INBOX/9 {38959}           copied to INBOX/9          5.38 msgs/s  1.088 MiB/s 1.820 MiB copied ETA: Tue Nov 24 16:51:10 2020  3 s  15/24 msgs left
msg INBOX/10 {40683}          copied to INBOX/10         5.58 msgs/s  1.038 MiB/s 1.858 MiB copied ETA: Tue Nov 24 16:51:10 2020  3 s  14/24 msgs left
msg INBOX/11 {42052}          copied to INBOX/11         5.76 msgs/s  0.994 MiB/s 1.898 MiB copied ETA: Tue Nov 24 16:51:10 2020  2 s  13/24 msgs left
msg INBOX/12 {10811}          copied to INBOX/12         6.00 msgs/s  976.525 KiB/s 1.909 MiB copied ETA: Tue Nov 24 16:51:09 2020  2 s  12/24 msgs left
msg INBOX/13 {16406}          copied to INBOX/13         6.14 msgs/s  930.148 KiB/s 1.924 MiB copied ETA: Tue Nov 24 16:51:09 2020  2 s  11/24 msgs left
msg INBOX/14 {15077}          copied to INBOX/14         6.33 msgs/s  897.916 KiB/s 1.939 MiB copied ETA: Tue Nov 24 16:51:09 2020  2 s  10/24 msgs left
msg INBOX/15 {19150}          copied to INBOX/15         6.44 msgs/s  860.988 KiB/s 1.957 MiB copied ETA: Tue Nov 24 16:51:09 2020  1 s  9/24 msgs left
msg INBOX/16 {7796}           copied to INBOX/16         6.62 msgs/s  831.754 KiB/s 1.965 MiB copied ETA: Tue Nov 24 16:51:09 2020  1 s  8/24 msgs left
msg INBOX/17 {1542272}        copied to INBOX/17         6.23 msgs/s  1.260 MiB/s 3.435 MiB copied ETA: Tue Nov 24 16:51:09 2020  1 s  7/24 msgs left
msg INBOX/18 {7824}           copied to INBOX/18         6.35 msgs/s  1.215 MiB/s 3.443 MiB copied ETA: Tue Nov 24 16:51:09 2020  1 s  6/24 msgs left
msg INBOX/19 {19579}          copied to INBOX/19         6.44 msgs/s  1.173 MiB/s 3.461 MiB copied ETA: Tue Nov 24 16:51:09 2020  1 s  5/24 msgs left
ETA: Tue Nov 24 16:51:09 2020  1 s  5/24 msgs left
Folder     2/2 [Spam]                              -> [Spam]                             
Host1: folder [Spam] has 5 messages in total (mentioned by SELECT)
Creating folder [Spam] on host2
Created folder [Spam] on host2
Host2: folder [Spam] has 0 messages in total (mentioned by SELECT)
Host2: folder [Spam] permanentflags: 
Host2: Subscribing to folder Spam
Host1: folder [Spam] considering 5 messages
Host2: folder [Spam] considering 0 messages
Host1: folder [Spam] selected 5 messages, duplicates 0
Host2: folder [Spam] selected 0 messages, duplicates 0
msg Spam/1 {182669}          copied to Spam/1          5.80 msgs/s  1.054 MiB/s 3.636 MiB copied ETA: Tue Nov 24 16:51:10 2020  1 s  4/24 msgs left
msg Spam/2 {13146}           copied to Spam/2          5.93 msgs/s  1.030 MiB/s 3.648 MiB copied ETA: Tue Nov 24 16:51:09 2020  1 s  3/24 msgs left
msg Spam/3 {14823}           copied to Spam/3          6.05 msgs/s  1.008 MiB/s 3.662 MiB copied ETA: Tue Nov 24 16:51:09 2020  0 s  2/24 msgs left
msg Spam/4 {14556}           copied to Spam/4          6.17 msgs/s  0.987 MiB/s 3.676 MiB copied ETA: Tue Nov 24 16:51:09 2020  0 s  1/24 msgs left
msg Spam/5 {43901}           copied to Spam/5          6.24 msgs/s  990.624 KiB/s 3.718 MiB copied ETA: Tue Nov 24 16:51:09 2020  0 s  0/24 msgs left
ETA: Tue Nov 24 16:51:09 2020  0 s  0/24 msgs left
++++ End looping on each folder

Folders sizes after the synchronization.
You can remove this foldersizes listing by using  "--nofoldersizesatend"
Host1 folder     1/2 [INBOX]                             Size:   3629603 Messages:    19 Biggest:   1542272
Host2 folder     1/2 [INBOX]                             Size:   3629630 Messages:    19 Biggest:   1542272
Host2-Host1                                                           27               0                  0

Host1 folder     2/2 [Spam]                              Size:    269069 Messages:     5 Biggest:    182669
Host2 folder     2/2 [Spam]                              Size:    269095 Messages:     5 Biggest:    182669
Host2-Host1                                                           26               0                  0

Host1 Nb folders:                     2 folders
Host2 Nb folders:                     2 folders

Host1 Nb messages:                   24 messages
Host2 Nb messages:                   24 messages

Host1 Total size:               3898672 bytes (3.718 MiB)
Host2 Total size:               3898725 bytes (3.718 MiB)

Host1 Biggest message:          1542272 bytes (1.471 MiB)
Host2 Biggest message:          1542272 bytes (1.471 MiB)

Time spent on sizing:         0.4 seconds
++++ Statistics
Transfer started on                     : Tue Nov 24 16:51:04 2020
Transfer ended on                       : Tue Nov 24 16:51:10 2020
Transfer time                           : 5.6 sec
Folders synced                          : 2/2 synced
Messages transferred                    : 24 
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                 : 3898725 (3.718 MiB)
Total bytes skipped                     : 0 (0.000 KiB)
Message rate                            : 4.2 messages/s
Average bandwidth rate                  : 674.1 KiB/s
Reconnections to host1                  : 0
Reconnections to host2                  : 0
Memory consumption at the end           : 171.9 MiB (started with 159.9 MiB)
Load end is                             : 1.60 1.82 1.81 3/1233 on 2 cores
Biggest message                         : 1542272 bytes (1.471 MiB)
Memory/biggest message ratio            : 116.9
Start difference host2 - host1          : -24 messages, -3898672 bytes (-3.718 MiB)
Final difference host2 - host1          : 0 messages, 53 bytes (0.052 KiB)
The sync looks good, all 24 identified messages in host1 are on host2.
There is no unidentified message
The sync is strict, all 24 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_24_16_51_04_523_profesionalni.kupci@mojatapeta.rs_profesionalni.kupci@mojatapeta.rs.txt ( to change it, use --logfile filepath ; or use --nolog to turn off logging )
