diff --git a/Zend/zend_fibers.h b/Zend/zend_fibers.h
index 33c85d5d64687..39dc0916debc7 100644
--- a/Zend/zend_fibers.h
+++ b/Zend/zend_fibers.h
@@ -87,6 +87,9 @@ struct _zend_fiber_context {
 
 	/* Fiber status. */
 	zend_fiber_status status;
+
+	/* Reserved for extensions */
+	void *reserved[ZEND_MAX_RESERVED_RESOURCES];
 };
 
 struct _zend_fiber {