diff --git a/admin/tool/messageinbound/classes/manager.php b/admin/tool/messageinbound/classes/manager.php
index 61152721af7..c42d87b462d 100644
--- a/admin/tool/messageinbound/classes/manager.php
+++ b/admin/tool/messageinbound/classes/manager.php
@@ -829,7 +829,7 @@ class manager {
 
         // An auto-reply may itself include the Bulk Precedence.
         $precedence = $messagedata->getHeaderText(0, \Horde_Imap_Client_Data_Fetch::HEADER_PARSE)->getValue('Precedence');
-        $isbulk = $isbulk || strtolower($precedence) == 'bulk';
+        $isbulk = $isbulk || strtolower($precedence ?? '') == 'bulk';
 
         // If the X-Autoreply header is set, and not 'no', then this is an automatic reply.
         $autoreply = $messagedata->getHeaderText(0, \Horde_Imap_Client_Data_Fetch::HEADER_PARSE)->getValue('X-Autoreply');
diff --git a/lib/classes/message/inbound/address_manager.php b/lib/classes/message/inbound/address_manager.php
index 1f4cb83be47..921d59af172 100644
--- a/lib/classes/message/inbound/address_manager.php
+++ b/lib/classes/message/inbound/address_manager.php
@@ -456,12 +456,27 @@ class address_manager {
      * @return string The encoded binary data
      */
     protected function pack_int($int) {
+        // If PHP environment is running on a 64-bit.
         if (PHP_INT_SIZE === 8) {
-            $l = intdiv($int, pow(2, 32)); // 32-bit integer quotient.
-            $r = $int % pow(2, 32); // 32-bit integer remaining.
+            // Will be used to ensures that the result remains as a 32-bit unsigned integer and
+            // doesn't extend beyond 32 bits.
+            $notation = 0xffffffff;
 
+            if ($int < 0) {
+                // If the given integer is negative, set it to -1.
+                $l = -1;
+            } else {
+                // Otherwise, calculate the upper 32 bits of the 64-bit integer.
+                $l = ($int >> 32) & $notation;
+            }
+
+            // Calculate the lower 32 bits of the 64-bit integer.
+            $r = $int & $notation;
+
+            // Pack the values of $l (upper 32 bits) and $r (lower 32 bits) into a binary string format.
             return pack('NN', $l, $r);
         } else {
+            // Pack the values into a binary string format.
             return pack('NN', 0, $int);
         }
     }
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index 900f9877a7f..0467ff5e3a8 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -3308,5 +3308,12 @@ privatefiles,moodle|/user/files.php';
         upgrade_main_savepoint(true, 2023042402.11);
     }
 
+    if ($oldversion < 2023042402.14) {
+        // Delete datakey with datavalue -1.
+        $DB->delete_records('messageinbound_datakeys', ['datavalue' => '-1']);
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2023042402.14);
+    }
+
     return true;
 }
diff --git a/version.php b/version.php
index 7d8d6abd4d7..42661a23066 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2023042402.13;              // 20230424      = branching date YYYYMMDD - do not modify!
+$version  = 2023042402.14;              // 20230424      = branching date YYYYMMDD - do not modify!
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.
 $release  = '4.2.2+ (Build: 20231004)'; // Human-friendly version name