diff --git a/modules/system/system.admin.inc b/modules/system/system.admin.inc
index b7e6fc9e706b242579da836dc27fe1a5e5e9be30..40908c1a277995d6378099a060fd092f94cbad1e 100644
--- a/modules/system/system.admin.inc
+++ b/modules/system/system.admin.inc
@@ -839,7 +839,7 @@ function system_modules($form, $form_state = array()) {
       elseif (isset($visible_files[$requires])) {
         $requires_name = $files[$requires]->info['name'];
         // Disable this module if it is incompatible with the dependency's version.
-        if ($incompatible_version = drupal_check_incompatibility($v, str_replace(DRUPAL_CORE_COMPATIBILITY . '-', '', $files[$requires]->info['version']))) {
+        if ($incompatible_version = drupal_check_incompatibility($v, str_replace(DRUPAL_CORE_COMPATIBILITY . '-', '', (string) $files[$requires]->info['version']))) {
           $extra['requires'][$requires] = t('@module (<span class="admin-missing">incompatible with</span> version @version)', array(
             '@module' => $requires_name . $incompatible_version,
             '@version' => $files[$requires]->info['version'],
diff --git a/modules/system/system.install b/modules/system/system.install
index 4f3b28991da51a7357ea36b704740eb5d4791eba..3714c8e501c36604d3a530b7992fda83122109c4 100644
--- a/modules/system/system.install
+++ b/modules/system/system.install
@@ -489,7 +489,7 @@ function system_requirements($phase) {
         // Check for an incompatible version.
         $required_file = $files[$required_module];
         $required_name = $required_file->info['name'];
-        $version = str_replace(DRUPAL_CORE_COMPATIBILITY . '-', '', $required_file->info['version']);
+        $version = str_replace(DRUPAL_CORE_COMPATIBILITY . '-', '', (string) $required_file->info['version']);
         $compatibility = drupal_check_incompatibility($requirement, $version);
         if ($compatibility) {
           $compatibility = rtrim(substr($compatibility, 2), ')');