diff --git a/datamodels/2.x/itop-backup/check-backup.php b/datamodels/2.x/itop-backup/check-backup.php
index 16a6ab06d..30b1c956d 100644
--- a/datamodels/2.x/itop-backup/check-backup.php
+++ b/datamodels/2.x/itop-backup/check-backup.php
@@ -102,14 +102,19 @@ if (!function_exists('sys_get_temp_dir'))
 }
 
 
-
+/**
+ * @param int $iRefTime Reference date time as a unix timestamp
+ *
+ * @return string Absolute path to the backup file, WITHOUT the file extension (`.tar.gz`)
+ * @throws \Exception
+ */
 function MakeArchiveFileName($iRefTime = null)
 {
 	$sDefaultBackupFileName = sys_get_temp_dir().'/'."__DB__-%Y-%m-%d";
 	$sBackupFile =  utils::ReadParam('backup_file', $sDefaultBackupFileName, true, 'raw_data');
 
 	$oBackup = new DBBackup();
-	$oDateTime = $iRefTime !== null ? new DateTime($iRefTime) : new DateTime();
+	$oDateTime = $iRefTime !== null ? DateTime::createFromFormat('U', $iRefTime) : new DateTime();
 	$sBackupFile = $oBackup->MakeName($sBackupFile, $oDateTime);
 
 	return $sBackupFile;
diff --git a/setup/backup.class.inc.php b/setup/backup.class.inc.php
index 3d5817398..9b38db6b8 100644
--- a/setup/backup.class.inc.php
+++ b/setup/backup.class.inc.php
@@ -146,13 +146,13 @@ class DBBackup
 	/**
 	 * Create a normalized backup name, depending on the current date/time and Database
 	 *
-	 * @param string sNameSpec Name and path, eventually containing itop placeholders + time formatting following the strftime() format {@link https://www.php.net/manual/fr/function.strftime.php}
+	 * @param string $sNameSpec Name and path, eventually containing itop placeholders + time formatting following the strftime() format {@link https://www.php.net/manual/fr/function.strftime.php}
 	 * @param \DateTime|null $oDateTime Date time to use for the name
 	 *
-	 * @return string
-	 * @since 3.1.0 N°5279 Add $oDtaeaTime parameter
+	 * @return string Name of the backup file WITHOUT the file extension (eg. `.tar.gz`)
+	 * @since 3.1.0 N°5279 Add $oDateTime parameter
 	 */
-	public function MakeName($sNameSpec = "__DB__-%Y-%m-%d", DateTime $oDateTime = null)
+	public function MakeName(string $sNameSpec = "__DB__-%Y-%m-%d", DateTime $oDateTime = null)
 	{
 		if ($oDateTime === null) {
 			$oDateTime = new DateTime();