diff --git a/src/js/bootstrap-dialog.js b/src/js/bootstrap-dialog.js
index d05f040..d4d5dea 100644
--- a/src/js/bootstrap-dialog.js
+++ b/src/js/bootstrap-dialog.js
@@ -54,7 +54,7 @@
             version = 'v3.2';
         } else if (/3\.3\.[1,2]/.test($.fn.modal.Constructor.VERSION)) {
             version = 'v3.3';  // v3.3.1, v3.3.2
-        } else if (/4\.0\.\d+/.test($.fn.modal.Constructor.VERSION)) {
+        } else if (/4\.0\.\d+(-(alpha|beta|rc)\.\d+)?/.test($.fn.modal.Constructor.VERSION)) {
             version = 'v4.0';
         } else {
             version = 'v3.3.4';