diff --git a/ampel-firmware/web_server.cpp b/ampel-firmware/web_server.cpp
index 1a43b50318748891cf1ed8e2fec4ba3068cd8cfc..3441b0b0c24402b2e4dfae973a6059850c364a36 100644
--- a/ampel-firmware/web_server.cpp
+++ b/ampel-firmware/web_server.cpp
@@ -41,7 +41,7 @@ namespace web_server {
             "<link rel='stylesheet' href='https://unpkg.com/purecss@2.0.6/build/pure-min.css'>"
             "<link rel='stylesheet' href='https://unpkg.com/purecss@2.0.6/build/grids-responsive-min.css'>"
             // JS Graphs:
-            "<script src='https://cdn.plot.ly/plotly-basic-1.58.2.min.js'></script>"
+            "<script src='https://cdn.plot.ly/plotly-basic-2.9.0.min.js'></script>"
             // Fullscreen
             "<meta name='viewport' content='width=device-width, initial-scale=1'>"
             // Refresh after every measurement.