diff --git a/api/src/Mail/Imap.php b/api/src/Mail/Imap.php
index 292e88e536..f5677f1d81 100644
--- a/api/src/Mail/Imap.php
+++ b/api/src/Mail/Imap.php
@@ -187,6 +187,23 @@ class Imap extends Horde_Imap_Client_Socket implements Imap\PushIface
 					'cacheob' => new Cache(),
 				)),
 			);
+			$config = Config::read('mail');
+			// fix for Dovecot private seen flags: we must NOT allow Horde to cache flags (otherwise Seen does NOT change!)
+			if (!empty($config['disable_caching']))
+			{
+				$parent_params['cache']['fields'] = [
+					'envelope'  => Horde_Imap_Client::FETCH_ENVELOPE,
+					'flags'     => Horde_Imap_Client::FETCH_FLAGS,
+					'headers'   => Horde_Imap_Client::FETCH_HEADERS,
+					'imapdate'  => Horde_Imap_Client::FETCH_IMAPDATE,
+					'size'      => Horde_Imap_Client::FETCH_SIZE,
+					'structure' => Horde_Imap_Client::FETCH_STRUCTURE
+				];
+				foreach((array)$config['disable_caching'] as $disable)
+				{
+					unset($parent_params['cache']['fields'][$disable]);
+				}
+			}
 		}
 		// uncomment to enable imap log for a single user
 		//if ($GLOBALS['egw_info']['user']['account_lid'] === 'username') $parent_params['debug'] = '/var/lib/egroupware/'.$_SERVER['HTTP_HOST'].'/imap.log';
diff --git a/mail/lang/egw_de.lang b/mail/lang/egw_de.lang
index ee299d4e93..1063d32ac2 100644
--- a/mail/lang/egw_de.lang
+++ b/mail/lang/egw_de.lang
@@ -80,6 +80,7 @@ blacklisted mails are marked as spam	mail	de	E-Mail-Adressen, die in die Blackli
 but check shared folders	mail	de	aber explizite Überprüfung der Ordner unterhalb der (Benutzer-)Freigaben
 by date	mail	de	nach Datum
 by default 'http://' is just replaced with 'https://'. feel free to configure 'https://proxy.egroupware.org/' to also load images only available via http.	mail	de	Als Vorgabe wird 'http://' nur durch 'https://' ersetzt. Sie können gerne 'https://proxy.egroupware.org/' eintragen, um Bilder anzuzeigen die ausschließlich per http geladen werden können.
+caching of flags	mail	de	Caching der Flags (z.B. Gelesen)
 can not open imap connection	mail	de	Keine Verbindung zum Mailserver möglich
 can not resolve the winmail.dat attachment!	mail	de	Der winmail.dat Anhang kann nicht geöffnet weden!
 canceled deletion due to user interaction	mail	de	Löschen durch Benutzer abgebrochen
@@ -141,6 +142,7 @@ deleting folders	mail	de	Ordner werden gelöscht
 deny certain groups access to following features	mail	de	Den Zugriff auf bestimmte Funktionen im E-Mail-Modul einschränken.
 directories have to be shared.	mail	de	Verzeichnisse müssen freigegeben werden.
 disable	mail	de	Deaktivieren
+disable caching of flags	mail	de	Caching von Flags ausschalten
 disable horizontal rule for separation of mail body from signature	mail	de	Signatur-Trennzeichen ausblenden
 disable use of flowed lines in plain text mails (rfc3676)	mail	de	Variablen Zeilenumbruch in text Mails (RFC3676) abschalten
 disabled!	mail	de	deaktiviert
@@ -201,6 +203,8 @@ enabled!	mail	de	aktiviert!
 encrypt	mail	de	Verschlüsseln
 encrypt your message with smime certificate	mail	de	Verschlüsseln Sie Ihre Nachricht mit einem S/MIME-Zertifikat
 encryption	mail	de	Verschlüsselung
+enable	mail	de	Einschalten
+enabled	mail	de	Eingeschaltet
 enter the name for the new folder:	mail	de	Tragen Sie hier den Namen für den neuen Ordner ein:
 error saving %1!	mail	de	Fehler beim Speichern von %1!
 error while setting acl for folder %1!	mail	de	Fehler beim Speichern von Zugriffsrechten für den Ordner %1!
@@ -482,6 +486,7 @@ report as ham	mail	de	Als "gute E-Mail" kennzeichnen
 report as spam	mail	de	Als Spam kennzeichnen
 report this email content as ham (not spam) - spam solutions like spamtitan will learn	mail	de	Markiert die Nachricht als "gute E-Mail" (kein Spam) - Spam-Lösungen wie SpamTitan lernen entsprechend
 report this email content as spam - spam solutions like spamtitan will learn	mail	de	Markiert die Nachricht als Spam - Spam-Lösungen wie SpamTitan lernen entsprechend
+required to disable if you use dovecot with private seen flags on shared or user folder!	mail	de	Muss ausgeschaltet werden, wenn Sie Dovecot mit privaten Gelesen Flags auf geteilten oder freigegebenen Ordnern benutzern!
 required pear class mail/mimedecode.php not found.	mail	de	Die benötigte PEAR Klasse Mail/mimeDecode.php konnte nicht gefunden werden.
 resend after how many days?	mail	de	Nach wie vielen Tagen erneut senden?
 respond to mail sent to:	mail	de	Benachrichtigung für
diff --git a/mail/lang/egw_en.lang b/mail/lang/egw_en.lang
index ba7883be40..ea09722ca0 100644
--- a/mail/lang/egw_en.lang
+++ b/mail/lang/egw_en.lang
@@ -80,6 +80,7 @@ blacklisted mails are marked as spam	mail	en	Blacklisted mails are marked as spa
 but check shared folders	mail	en	but check shared folders
 by date	mail	en	By date
 by default 'http://' is just replaced with 'https://'. feel free to configure 'https://proxy.egroupware.org/' to also load images only available via http.	mail	en	By default 'http://' is just replaced with 'https://'. Feel free to configure 'https://proxy.egroupware.org/' to also load images only available via http.
+caching of flags	mail	en	Caching of flags
 can not open imap connection	mail	en	Can not open IMAP connection
 can not resolve the winmail.dat attachment!	mail	en	Can not resolve the winmail.dat attachment!
 canceled deletion due to user interaction	mail	en	canceled deletion due to user interaction
@@ -141,6 +142,7 @@ deleting folders	mail	en	Deleting folders
 deny certain groups access to following features	mail	en	Deny certain groups access to following features
 directories have to be shared.	mail	en	Directories have to be shared.
 disable	mail	en	Disable
+disable caching of flags	mail	en	Disable caching of flags
 disable horizontal rule for separation of mail body from signature	mail	en	disable horizontal rule for separation of mail body from signature
 disable use of flowed lines in plain text mails (rfc3676)	mail	en	Disable use of flowed lines in plain text mails (RFC3676)
 disabled!	mail	en	disabled!
@@ -197,6 +199,7 @@ empty junk	mail	en	empty junk/spam folder
 empty trash	mail	en	empty trash
 empty trash and junk	mail	en	Empty Trash and Junk
 enable	mail	en	Enable
+enabled	mail	en	Enabled
 enabled!	mail	en	enabled!
 encrypt	mail	en	Encrypt
 encrypt your message with smime certificate	mail	en	Encrypt your message with S/MIME certificate
@@ -483,6 +486,7 @@ report as spam	mail	en	Report as Spam
 report this email content as ham (not spam) - spam solutions like spamtitan will learn	mail	en	Report this email content as Ham (not spam) - spam solutions like spamTitan will learn
 report this email content as spam - spam solutions like spamtitan will learn	mail	en	Report this email content as Spam - spam solutions like spamTitan will learn
 required pear class mail/mimedecode.php not found.	mail	en	Required PEAR class Mail/mimeDecode.php not found.
+required to disable if you use dovecot with private seen flags on shared or user folder!	mail	en	Required to disable if you use Dovecot with private seen flags on shared or user folder!
 resend after how many days?	mail	en	Resend after how many days?
 respond to mail sent to:	mail	en	Respond to mail sent to:
 restrict acl management	admin	en	restrict acl management
diff --git a/mail/templates/default/config.xet b/mail/templates/default/config.xet
index 5fe69421ff..4f11237442 100644
--- a/mail/templates/default/config.xet
+++ b/mail/templates/default/config.xet
@@ -100,6 +100,16 @@
 						<option value="True">Yes</option>
 					</select>
 				</row>
+				<row>
+					<vbox>
+						<description value="Caching of flags"/>
+						<description value="Required to disable if you use Dovecot with private seen flags on shared or user folder!"/>
+					</vbox>
+					<select id="newsettings[disble_caching]">
+						<option value="">{Enabled} ({default})</option>
+						<option value="flags">Disable caching of flags</option>
+					</select>
+				</row>
 				<row>
 					<vbox>
 						<description value="Disable use of flowed lines in plain text mails (RFC3676)"/>