Here is imapsync 1.977 on host privremena, a linux system with 12.7/31.3 free GiB of RAM
with Perl 5.28.1 and Mail::IMAPClient 3.42
Transfer started at Tue Nov 24 18:13:13 2020
PID is 8012 my PPID is 8011
Log file is LOG_imapsync/2020_11_24_18_13_13_262_info@virtuelni-inkubator.rs_info@virtuelni-inkubator.rs.txt ( to change it, use --logfile path ; or use --nolog to turn off logging )
Load is 1.34 1.68 1.69 2/1226 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 info@virtuelni-inkubator.rs --user2 info@virtuelni-inkubator.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=37; 686c9b6492d74d6d7c41621a12c6956f=la6q3dnkojbe6vjjq7boesovf2
kill -QUIT 8012 # special behavior: call to sub catch_exit
kill -TERM 8012 # special behavior: call to sub catch_exit
kill -INT 8012 # special behavior: call to sub catch_reconnect
kill -HUP 8012 # special behavior: call to sub catch_print
kill -USR1 8012 # special behavior: call to sub toggle_sleep
File ./imapsync_188.93.125.32_info@virtuelni-inkubator.rs_194.146.57.50_info@virtuelni-inkubator.rs.pid does not exist
Error reading file ./imapsync_188.93.125.32_info@virtuelni-inkubator.rs_194.146.57.50_info@virtuelni-inkubator.rs.pid : No such file or directory
PID file is ./imapsync_188.93.125.32_info@virtuelni-inkubator.rs_194.146.57.50_info@virtuelni-inkubator.rs.pid ( to change it, use --pidfile filepath ; to avoid it use --pidfile "" )
Writing my PID 8012 in ./imapsync_188.93.125.32_info@virtuelni-inkubator.rs_194.146.57.50_info@virtuelni-inkubator.rs.pid
Writing also my logfile name in ./imapsync_188.93.125.32_info@virtuelni-inkubator.rs_194.146.57.50_info@virtuelni-inkubator.rs.pid : LOG_imapsync/2020_11_24_18_13_13_262_info@virtuelni-inkubator.rs_info@virtuelni-inkubator.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 [info@virtuelni-inkubator.rs]
Host2: IMAP server [194.146.57.50] port [993] user [info@virtuelni-inkubator.rs]
Host1: connecting and login on host1 [188.93.125.32] port [143] with user [info@virtuelni-inkubator.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 [info@virtuelni-inkubator.rs] auth [LOGIN]
Host2: connecting and login on host2 [194.146.57.50] port [993] with user [info@virtuelni-inkubator.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 [info@virtuelni-inkubator.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 5 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) "." Trash
* LIST (\HasNoChildren) "." Drafts
* LIST (\HasNoChildren) "." Sent
* LIST (\HasNoChildren) "." Junk
* LIST (\HasNoChildren) "." INBOX
15 OK List completed.

[Drafts]
[INBOX]
[Junk]
[Sent]
[Trash]

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     1/5 [Drafts]                            Size:         0 Messages:     0 Biggest:         0
Host2 folder     1/5 [Drafts]                             does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     2/5 [INBOX]                             Size:    232759 Messages:    14 Biggest:    178369
Host2 folder     2/5 [INBOX]                             Size:         0 Messages:     0 Biggest:         0
Host2-Host1                                                      -232759             -14            -178369

Host1 folder     3/5 [Junk]                              Size:         0 Messages:     0 Biggest:         0
Host2 folder     3/5 [Junk]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     4/5 [Sent]                              Size:         0 Messages:     0 Biggest:         0
Host2 folder     4/5 [Sent]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     5/5 [Trash]                             Size:         0 Messages:     0 Biggest:         0
Host2 folder     5/5 [Trash]                              does not exist yet
Host2-Host1                                                            0               0                  0

Host1 Nb folders:                     5 folders
Host2 Nb folders:                     5 folders

Host1 Nb messages:                   14 messages
Host2 Nb messages:                    0 messages

Host1 Total size:                232759 bytes (227.304 KiB)
Host2 Total size:                     0 bytes (0.000 KiB)

Host1 Biggest message:           178369 bytes (174.188 KiB)
Host2 Biggest message:                0 bytes (0.000 KiB)

Time spent on sizing:         1.6 seconds
++++ Looping on each one of 5 folders to sync
ETA: Tue Nov 24 18:13:14 2020  0 s  14/14 msgs left
Folder     1/5 [Drafts]                            -> [Drafts]                           
Host1: folder [Drafts] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [Drafts]
ETA: Tue Nov 24 18:13:15 2020  0 s  14/14 msgs left
Folder     2/5 [INBOX]                             -> [INBOX]                            
Host1: folder [INBOX] has 14 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 14 messages
Host2: folder [INBOX] considering 0 messages
Host1: folder [INBOX] selected 14 messages, duplicates 0
Host2: folder [INBOX] selected 0 messages, duplicates 0
msg INBOX/1 {1311}            copied to INBOX/1          2.66 msgs/s  3.400 KiB/s 1.280 KiB copied ETA: Tue Nov 24 18:13:20 2020  5 s  13/14 msgs left
msg INBOX/2 {4198}            copied to INBOX/2          4.28 msgs/s  11.518 KiB/s 5.380 KiB copied ETA: Tue Nov 24 18:13:18 2020  3 s  12/14 msgs left
msg INBOX/3 {4286}            copied to INBOX/3          5.29 msgs/s  16.865 KiB/s 9.565 KiB copied ETA: Tue Nov 24 18:13:17 2020  2 s  11/14 msgs left
msg INBOX/4 {4566}            copied to INBOX/4          6.07 msgs/s  21.283 KiB/s 14.024 KiB copied ETA: Tue Nov 24 18:13:17 2020  2 s  10/14 msgs left
msg INBOX/5 {3658}            copied to INBOX/5          6.67 msgs/s  23.483 KiB/s 17.597 KiB copied ETA: Tue Nov 24 18:13:16 2020  1 s  9/14 msgs left
msg INBOX/6 {4054}            copied to INBOX/6          7.13 msgs/s  25.620 KiB/s 21.556 KiB copied ETA: Tue Nov 24 18:13:16 2020  1 s  8/14 msgs left
msg INBOX/7 {3639}            copied to INBOX/7          7.51 msgs/s  26.955 KiB/s 25.109 KiB copied ETA: Tue Nov 24 18:13:16 2020  1 s  7/14 msgs left
msg INBOX/8 {3009}            copied to INBOX/8          7.83 msgs/s  27.445 KiB/s 28.048 KiB copied ETA: Tue Nov 24 18:13:16 2020  1 s  6/14 msgs left
msg INBOX/9 {178369}          copied to INBOX/9          7.05 msgs/s  158.447 KiB/s 202.236 KiB copied ETA: Tue Nov 24 18:13:16 2020  1 s  5/14 msgs left
msg INBOX/10 {5440}           copied to INBOX/10         7.32 msgs/s  151.876 KiB/s 207.549 KiB copied ETA: Tue Nov 24 18:13:16 2020  1 s  4/14 msgs left
msg INBOX/11 {6624}           copied to INBOX/11         7.54 msgs/s  146.748 KiB/s 214.018 KiB copied ETA: Tue Nov 24 18:13:16 2020  0 s  3/14 msgs left
msg INBOX/12 {3147}           copied to INBOX/12         7.74 msgs/s  140.042 KiB/s 217.091 KiB copied ETA: Tue Nov 24 18:13:16 2020  0 s  2/14 msgs left
msg INBOX/13 {5425}           copied to INBOX/13         7.91 msgs/s  135.313 KiB/s 222.389 KiB copied ETA: Tue Nov 24 18:13:16 2020  0 s  1/14 msgs left
msg INBOX/14 {5033}           copied to INBOX/14         8.07 msgs/s  130.990 KiB/s 227.304 KiB copied ETA: Tue Nov 24 18:13:16 2020  0 s  0/14 msgs left
ETA: Tue Nov 24 18:13:16 2020  0 s  0/14 msgs left
Folder     3/5 [Junk]                              -> [Junk]                             
Host1: folder [Junk] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [Junk]
ETA: Tue Nov 24 18:13:16 2020  0 s  0/14 msgs left
Folder     4/5 [Sent]                              -> [Sent]                             
Host1: folder [Sent] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [Sent]
ETA: Tue Nov 24 18:13:16 2020  0 s  0/14 msgs left
Folder     5/5 [Trash]                             -> [Trash]                            
Host1: folder [Trash] has 0 messages in total (mentioned by SELECT)
Host1: skipping empty host1 folder [Trash]
ETA: Tue Nov 24 18:13:16 2020  0 s  0/14 msgs left
++++ End looping on each folder

Folders sizes after the synchronization.
You can remove this foldersizes listing by using  "--nofoldersizesatend"
Host1 folder     1/5 [Drafts]                            Size:         0 Messages:     0 Biggest:         0
Host2 folder     1/5 [Drafts]                             does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     2/5 [INBOX]                             Size:    232759 Messages:    14 Biggest:    178369
Host2 folder     2/5 [INBOX]                             Size:    232759 Messages:    14 Biggest:    178369
Host2-Host1                                                            0               0                  0

Host1 folder     3/5 [Junk]                              Size:         0 Messages:     0 Biggest:         0
Host2 folder     3/5 [Junk]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     4/5 [Sent]                              Size:         0 Messages:     0 Biggest:         0
Host2 folder     4/5 [Sent]                               does not exist yet
Host2-Host1                                                            0               0                  0

Host1 folder     5/5 [Trash]                             Size:         0 Messages:     0 Biggest:         0
Host2 folder     5/5 [Trash]                              does not exist yet
Host2-Host1                                                            0               0                  0

Host1 Nb folders:                     5 folders
Host2 Nb folders:                     5 folders

Host1 Nb messages:                   14 messages
Host2 Nb messages:                   14 messages

Host1 Total size:                232759 bytes (227.304 KiB)
Host2 Total size:                232759 bytes (227.304 KiB)

Host1 Biggest message:           178369 bytes (174.188 KiB)
Host2 Biggest message:           178369 bytes (174.188 KiB)

Time spent on sizing:         0.4 seconds
++++ Statistics
Transfer started on                     : Tue Nov 24 18:13:13 2020
Transfer ended on                       : Tue Nov 24 18:13:17 2020
Transfer time                           : 3.9 sec
Folders synced                          : 5/5 synced
Messages transferred                    : 14 
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                 : 232759 (227.304 KiB)
Total bytes skipped                     : 0 (0.000 KiB)
Message rate                            : 3.6 messages/s
Average bandwidth rate                  : 58.6 KiB/s
Reconnections to host1                  : 0
Reconnections to host2                  : 0
Memory consumption at the end           : 164.4 MiB (started with 159.9 MiB)
Load end is                             : 1.31 1.67 1.68 2/1228 on 2 cores
Biggest message                         : 178369 bytes (174.188 KiB)
Memory/biggest message ratio            : 966.6
Start difference host2 - host1          : -14 messages, -232759 bytes (-227.304 KiB)
Final difference host2 - host1          : 0 messages, 0 bytes (0.000 KiB)
The sync looks good, all 14 identified messages in host1 are on host2.
There is no unidentified message
The sync is strict, all 14 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_18_13_13_262_info@virtuelni-inkubator.rs_info@virtuelni-inkubator.rs.txt ( to change it, use --logfile filepath ; or use --nolog to turn off logging )
