diff --git a/CHANGES.md b/CHANGES.md
index e6559a291c0..8f36e5cddf1 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,4 +1,5 @@
 # 6.5.4 2023-??-??
+ - 2023-08-11 Updated protocol to https for a secured communitation with gravatar.com.
  - 2023-08-11 Fixed SelectAll function in AdminDynamicFieldScreenConfiguration. Select only all visible elements.
  - 2023-08-11 Added additional note to DynamicFields::ScreenConfiguration::ConfigKeysOfScreensByObjectType###Framework for AgentTicketSearch (DynamicField|DefaultColumns).
  - 2023-08-11 Fixed - Installing a package with dependency not possible - Added additional check if any problem exists - means if any package or module is not installed.
diff --git a/Kernel/Output/HTML/Layout.pm b/Kernel/Output/HTML/Layout.pm
index 5950afe1e2f..b97d3af2472 100644
--- a/Kernel/Output/HTML/Layout.pm
+++ b/Kernel/Output/HTML/Layout.pm
@@ -1439,7 +1439,7 @@ sub Header {
             my $DefaultIcon = $ConfigObject->Get('Frontend::Gravatar::DefaultImage') || 'mp';
             $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Self->{UserEmail} );
             $Param{Avatar}
-                = '//www.gravatar.com/avatar/' . md5_hex( lc $Self->{UserEmail} ) . '?s=100&d=' . $DefaultIcon;
+                = 'https://www.gravatar.com/avatar/' . md5_hex( lc $Self->{UserEmail} ) . '?s=100&d=' . $DefaultIcon;
         }
         else {
             my %User = $Kernel::OM->Get('Kernel::System::User')->GetUserData(
diff --git a/Kernel/Output/HTML/Preferences/Avatar.pm b/Kernel/Output/HTML/Preferences/Avatar.pm
index 2aad4e2b808..85aecdf568f 100644
--- a/Kernel/Output/HTML/Preferences/Avatar.pm
+++ b/Kernel/Output/HTML/Preferences/Avatar.pm
@@ -43,7 +43,7 @@ sub Param {
 
     if ( $AvatarEngine eq 'Gravatar' && $Self->{UserEmail} ) {
         $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Self->{UserEmail} );
-        $Return->{Avatar} = '//www.gravatar.com/avatar/' . md5_hex( lc $Self->{UserEmail} ) . '?s=45&d=mp';
+        $Return->{Avatar} = 'https://www.gravatar.com/avatar/' . md5_hex( lc $Self->{UserEmail} ) . '?s=45&d=mp';
     }
 
     $Return->{UserEmailAddress} = $Param{UserData}->{UserEmail};
diff --git a/Kernel/Output/HTML/TicketZoom/Agent/Base.pm b/Kernel/Output/HTML/TicketZoom/Agent/Base.pm
index 086d51d041e..11402ab28e1 100644
--- a/Kernel/Output/HTML/TicketZoom/Agent/Base.pm
+++ b/Kernel/Output/HTML/TicketZoom/Agent/Base.pm
@@ -185,7 +185,7 @@ Get URL used for article sender image.
 
 Returns:
 
-    $SenderImage = '//gravatar.com/avatar/28a58af1db24962e81212115e7cac685?s=80';
+    $SenderImage = 'https://gravatar.com/avatar/28a58af1db24962e81212115e7cac685?s=80';
 
 =cut
 
@@ -218,7 +218,7 @@ sub _ArticleSenderImage {
                 }
             }
             $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Email );
-            $Result = '//www.gravatar.com/avatar/' . md5_hex( lc $Email ) . '?s=' . $Size . '&d=' . $DefaultIcon;
+            $Result = 'https://www.gravatar.com/avatar/' . md5_hex( lc $Email ) . '?s=' . $Size . '&d=' . $DefaultIcon;
         }
     }
 
diff --git a/scripts/test/Ticket/MetaArticle.t b/scripts/test/Ticket/MetaArticle.t
index 7e50b74e158..886cb81ca7c 100644
--- a/scripts/test/Ticket/MetaArticle.t
+++ b/scripts/test/Ticket/MetaArticle.t
@@ -379,7 +379,7 @@ my $SenderImage = $Kernel::OM->Get('Kernel::Output::HTML::TicketZoom::Agent::Bas
 
 $Self->Is(
     $SenderImage,
-    '//www.gravatar.com/avatar/' . md5_hex( lc $Email ) . '?s=80&d=' . $DefaultImage,
+    'https://www.gravatar.com/avatar/' . md5_hex( lc $Email ) . '?s=80&d=' . $DefaultImage,
     'Avatar link is generated successfully'
 );
 
@@ -391,7 +391,7 @@ $SenderImage = $Kernel::OM->Get('Kernel::Output::HTML::TicketZoom::Agent::Base')
 $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Email );
 $Self->Is(
     $SenderImage,
-    '//www.gravatar.com/avatar/' . md5_hex( lc $Email ) . '?s=80&d=' . $DefaultImage,
+    'https://www.gravatar.com/avatar/' . md5_hex( lc $Email ) . '?s=80&d=' . $DefaultImage,
     'Avatar link is generated successfully with utf-8 chars.'
 );