diff --git a/Documentation/SOGoInstallationGuide.asciidoc b/Documentation/SOGoInstallationGuide.asciidoc
index ad4fcbc89c..981436fda8 100644
--- a/Documentation/SOGoInstallationGuide.asciidoc
+++ b/Documentation/SOGoInstallationGuide.asciidoc
@@ -839,6 +839,9 @@ specified as an array of dictionaries.
 |S |SOGoURLEncryptionPassphrase
 |Passphrase for `SOGoURLEncryptionEnabled`. The string must be 128 bits (16 characters). If this settings change, the cache server must be restarted, and the DAV url will change. Default value is `SOGoSuperSecret0`.
 
+|D |SOGoForceRawHtmlSignature
+|Add `<div class="raw-html-embed sogo-raw-html-embed">` around signature to avoid CKEditor 5 modifying HTML code and breaking signature (https://bugs.sogo.nu/view.php?id=5920). Default value is `YES` (tag is added).
+
 |=======================================================================
 
 
@@ -3971,8 +3974,8 @@ current version of SOGo from the previous release.
 [cols="100a"]
 |=======================================================================
 
-h|5.10.1
-|Parameters `SOGoGlobalAddressBookFirstEntries` and `SOGoGlobalAddressBookFirstEntriesCount` has been removed. Please use `listRequiresDot` and `globalAddressBookFirstEntriesCount` instead
+h|5.11
+|Parameters `SOGoGlobalAddressBookFirstEntries` and `SOGoGlobalAddressBookFirstEntriesCount` has been removed. Please use `listRequiresDot` and `globalAddressBookFirstEntriesCount` instead. Signature are now between a div tag to avoid CKEditor changing the content - set `SOGoForceRawHtmlSignature` to `NO` to leave signature (https://bugs.sogo.nu/view.php?id=5920).
 
 h|5.9.0
 |Run the shell script `sql-update-5.8.4_to_5.9.0.sh` (if you are using MySQL). This will change the `c_defaults` to `MEDIUMTEXT`.
diff --git a/SoObjects/SOGo/SOGoDomainDefaults.h b/SoObjects/SOGo/SOGoDomainDefaults.h
index 54d7524eca..f7bddceee7 100644
--- a/SoObjects/SOGo/SOGoDomainDefaults.h
+++ b/SoObjects/SOGo/SOGoDomainDefaults.h
@@ -102,6 +102,8 @@
 
 - (NSString *) passwordRecoveryFrom;
 
+- (BOOL) forceRawHtmlSignature;
+
 @end
 
 #endif /* SOGODOMAINDEFAULTS_H */
diff --git a/SoObjects/SOGo/SOGoDomainDefaults.m b/SoObjects/SOGo/SOGoDomainDefaults.m
index 2ec86124e7..c67e83b59d 100644
--- a/SoObjects/SOGo/SOGoDomainDefaults.m
+++ b/SoObjects/SOGo/SOGoDomainDefaults.m
@@ -465,4 +465,9 @@ - (NSString *) passwordRecoveryFrom
   return emailFrom;
 }
 
+- (BOOL) forceRawHtmlSignature
+{
+  return [self objectForKey: @"SOGoForceRawHtmlSignature"] ? [self boolForKey: @"SOGoForceRawHtmlSignature"] : YES;
+}
+
 @end
diff --git a/SoObjects/SOGo/SOGoUser.h b/SoObjects/SOGo/SOGoUser.h
index ab43832a58..7460837ac0 100644
--- a/SoObjects/SOGo/SOGoUser.h
+++ b/SoObjects/SOGo/SOGoUser.h
@@ -113,6 +113,7 @@
 - (unsigned int) weekNumberForDate: (NSCalendarDate *) date;
 
 - (NSArray *) mailAccounts;
+- (NSArray *) mailAccountsNoRawHtmlSignature;
 - (NSArray *) mailAccountsWithDelegatedIdentities: (BOOL) appendDeletegatedIdentities;
 - (NSDictionary *) accountWithName: (NSString *) accountName;
 - (NSArray *) allIdentities;
diff --git a/SoObjects/SOGo/SOGoUser.m b/SoObjects/SOGo/SOGoUser.m
index fc224abaf4..f7047bacc3 100644
--- a/SoObjects/SOGo/SOGoUser.m
+++ b/SoObjects/SOGo/SOGoUser.m
@@ -1026,10 +1026,15 @@ - (void) _appendSystemMailAccountWithDelegatedIdentities: (BOOL) appendDeletegat
 
 - (NSArray *) mailAccounts
 {
-  return [self mailAccountsWithDelegatedIdentities: YES];
+  return [self mailAccountsWithDelegatedIdentities: YES forceRawHtmlSignature: [[self domainDefaults] forceRawHtmlSignature]];
 }
 
-- (NSArray *) mailAccountsWithDelegatedIdentities: (BOOL) appendDeletegatedIdentities
+- (NSArray *) mailAccountsNoRawHtmlSignature
+{
+  return [self mailAccountsWithDelegatedIdentities: YES forceRawHtmlSignature: NO];
+}
+
+- (NSArray *) mailAccountsWithDelegatedIdentities: (BOOL) appendDeletegatedIdentities forceRawHtmlSignature: (BOOL) forceRawHtmlSignature
 {
   NSArray *auxAccounts;
 
@@ -1112,8 +1117,9 @@ - (NSArray *) mailAccountsWithDelegatedIdentities: (BOOL) appendDeletegatedIdent
           if ([tmpIdentity objectForKey: @"signature"] ) {
             // Add raw html embed class
             if ([[tmpIdentity objectForKey: @"signature"] rangeOfString:@"raw-html-embed"].location == NSNotFound
-                && [[[self userDefaults] mailComposeMessageType] isEqualToString: @"html"]) {
-              signature = [NSString stringWithFormat:@"<div class=\"raw-html-embed\">%@</div>", [tmpIdentity objectForKey: @"signature"]];
+                && [[[self userDefaults] mailComposeMessageType] isEqualToString: @"html"]
+                && forceRawHtmlSignature) {
+              signature = [NSString stringWithFormat:@"<div class=\"raw-html-embed sogo-raw-html-embed\">%@</div>", [tmpIdentity objectForKey: @"signature"]];
               [tmpIdentity setObject:signature forKey:@"signature"];
             }
           }
diff --git a/UI/PreferencesUI/UIxJSONPreferences.m b/UI/PreferencesUI/UIxJSONPreferences.m
index 9eca0cdf18..a2cfd3f1f6 100644
--- a/UI/PreferencesUI/UIxJSONPreferences.m
+++ b/UI/PreferencesUI/UIxJSONPreferences.m
@@ -516,7 +516,7 @@ - (NSString *) jsonDefaults
         }
     }
   // We inject our default mail account
-  account = [[[context activeUser] mailAccounts] objectAtIndex: 0];
+  account = [[[context activeUser] mailAccountsNoRawHtmlSignature] objectAtIndex: 0];
   if (![account objectForKey: @"receipts"])
     {
       [account setObject: [NSDictionary dictionaryWithObjectsAndKeys: @"ignore", @"receiptAction",
diff --git a/UI/WebServerResources/scss/views/MailerUI.scss b/UI/WebServerResources/scss/views/MailerUI.scss
index 7253d037ff..a5108f8f82 100644
--- a/UI/WebServerResources/scss/views/MailerUI.scss
+++ b/UI/WebServerResources/scss/views/MailerUI.scss
@@ -428,4 +428,28 @@ md-dialog md-dialog-actions.sg-mail-editor-attachments {
     margin-left: unset!important;
     margin-right: unset!important;
   }
+
+  .ck-widget.sogo-raw-html-embed:before {
+    display: none!important;
+  }
+
+  .sogo-raw-html-embed .raw-html-embed__buttons-wrapper {
+    display: none !important;
+  }
+
+  .ck-widget.sogo-raw-html-embed:not(.ck-widget_selected):not(:hover) {
+    outline: none!important;
+  }
+
+  .ck-widget.sogo-raw-html-embed {
+    background-color: unset;
+  }
+  
+  .ck-widget.sogo-raw-html-embed .raw-html-embed__preview-content {
+    background-color: unset;
+  }
+
+  .sogo-raw-html-embed .raw-html-embed__preview-placeholder {
+    display: none !important;
+  }
 }
\ No newline at end of file