diff --git a/web/app/libs/uoj-lib.php b/web/app/libs/uoj-lib.php
index d43a11b..afea464 100644
--- a/web/app/libs/uoj-lib.php
+++ b/web/app/libs/uoj-lib.php
@@ -13,7 +13,7 @@ function requireLib($name) { // html lib
 	$REQUIRE_LIB[$name] = '';
 }
 function requirePHPLib($name) { // uoj php lib
-	require $_SERVER['DOCUMENT_ROOT'] . '/app/libs/uoj-' . $name . '-lib.php';
+	require_once $_SERVER['DOCUMENT_ROOT'] . '/app/libs/uoj-' . $name . '-lib.php';
 }
 
 requirePHPLib('expection');
diff --git a/web/app/upgrade/39_limits_in_extra_config/upgrade.php b/web/app/upgrade/39_limits_in_extra_config/upgrade.php
new file mode 100644
index 0000000..04fc26e
--- /dev/null
+++ b/web/app/upgrade/39_limits_in_extra_config/upgrade.php
@@ -0,0 +1,37 @@
+<?php
+
+requirePHPLib('data');
+
+return function ($type) {
+	if ($type == 'up') {
+		DB::init();
+
+		$problems = DB::selectAll("select * from problems");
+
+		foreach ($problems as $info) {
+			$problem = new UOJProblem($info);
+
+			$extra_config = $problem->getExtraConfig();
+			$problem_conf = $problem->getProblemConf();
+
+			if (!($problem_conf instanceof UOJProblemConf)) {
+				continue;
+			}
+
+			$extra_config['time_limit'] = (float)$problem_conf->getVal('time_limit', 1);
+			$extra_config['memory_limit'] = (int)$problem_conf->getVal('memory_limit', 256);
+
+			DB::update([
+				"update problems",
+				"set", [
+					"extra_config" => json_encode($extra_config, JSON_FORCE_OBJECT),
+				],
+				"where", [
+					"id" => $problem->info['id'],
+				],
+			]);
+
+			echo "Problem {$problem->info['id']} upgraded.\n";
+		}
+	}
+};