Ticket #52513: 52513.diff

src/wp-admin/update-core.php

@@ -55 +55 @@
                 $current = true;
         }
 
-        $is_development_version = preg_match( '/alpha|beta|RC/', $version_string );
-
         $message       = '';
-        $submit        = $is_development_version ? __( 'Update to latest nightly' ) : __( 'Update now' );
         $form_action   = 'update-core.php?action=do-core-upgrade';
         $php_version   = phpversion();
         $mysql_version = $wpdb->db_version();
         $show_buttons  = true;
 
+        // Nightly build versions have two hyphens and a commit number.
+        if ( preg_match( '/-\w+-\d+/', $update->current ) ) {
+                // Retrieve the major version number.
+                preg_match( '/^\d+.\d+/', $update->current, $update_major );
+                /* translators: %s: WordPress version. */
+                $submit = sprintf( __( 'Update to latest %s nightly' ), $update_major[0] );
+        } else {
+                /* translators: %s: WordPress version. */
+                $submit = sprintf( __( 'Update to version %s' ), $version_string );
+        }
+
         if ( 'development' === $update->response ) {
                 $message = __( 'You can update to the latest nightly build manually:' );
         } else {