diff --git a/main.go b/main.go
index 8edd01c..d9e693b 100644
--- a/main.go
+++ b/main.go
@@ -23,7 +23,7 @@ import (
 	"text/template"
 )
 
-const VERSION = "v5"
+const VERSION = "v4"
 const CONTEXT_USER = 1
 const SYNC_PAGINATION = 200
 
diff --git a/static/service_worker.js b/static/service_worker.js
index 1717eef..4a5f71d 100644
--- a/static/service_worker.js
+++ b/static/service_worker.js
@@ -24,6 +24,7 @@ const CACHED_ASSETS = [
 	'/js/{{ .VERSION }}/crypto.mjs',
 	'/js/{{ .VERSION }}/key.mjs',
 	'/js/{{ .VERSION }}/lib/custom_html_element.mjs',
+	'/js/{{ .VERSION }}/lib/fullcalendar.min.js',
 	'/js/{{ .VERSION }}/lib/node_modules/marked/lib/marked.esm.js',
 	'/js/{{ .VERSION }}/lib/node_modules/marked-token-position/lib/index.esm.js',
 	'/js/{{ .VERSION }}/lib/sjcl.js',