diff --git a/cosmogramme/sql/patch/patch_203.php b/cosmogramme/sql/patch/patch_203.php
index 4ff3274545f71c8d1db30442fc6b309398548eba..c1a5ac703f45ac4c93295ef9885194d6ba557ee8 100644
--- a/cosmogramme/sql/patch/patch_203.php
+++ b/cosmogramme/sql/patch/patch_203.php
@@ -20,8 +20,12 @@ for ($i = 1; $i <= $page_count; ++$i) {
 		}
 
 		// already serialized array, do nothing
-		if (is_array(unserialize($zone_995)))
+		set_error_handler(function() {});
+		if (is_array(unserialize($zone_995))) {
+			restore_error_handler();
 			continue;
+		}
+		restore_error_handler();
 
 		$values = explode(' ', $zone_995);
 		$new_zone_995 = [];