diff --git a/templates/index.htm b/templates/index.htm
index 9d4089d..4f20134 100644
--- a/templates/index.htm
+++ b/templates/index.htm
@@ -2,15 +2,15 @@
 <html>
     <head>
         <title>Real time streaming</title>
-        <script src="https://d3js.org/d3-array.v2.min.js"></script>
-        <script src="https://d3js.org/d3-color.v1.min.js"></script>
-        <script src="https://d3js.org/d3-format.v1.min.js"></script>
-        <script src="https://d3js.org/d3-interpolate.v1.min.js"></script>
-        <script src="https://d3js.org/d3-time.v1.min.js"></script>
-        <script src="https://d3js.org/d3-time-format.v2.min.js"></script>
-        <script src="https://d3js.org/d3-scale.v3.min.js"></script>
-        <script src="https://d3js.org/d3-selection.v1.min.js"></script>
-        <script src="https://d3js.org/d3-axis.v1.min.js"></script>
+        <script src="https://cdn.jsdelivr.net/npm/d3-array@3"></script>
+        <script src="https://cdn.jsdelivr.net/npm/d3-color@3"></script>
+        <script src="https://cdn.jsdelivr.net/npm/d3-format@3"></script>
+        <script src="https://cdn.jsdelivr.net/npm/d3-interpolate@3"></script>
+        <script src="https://cdn.jsdelivr.net/npm/d3-time@3"></script>
+        <script src="https://cdn.jsdelivr.net/npm/d3-time-format@4"></script>
+        <script src="https://cdn.jsdelivr.net/npm/d3-scale@4"></script>
+        <script src="https://cdn.jsdelivr.net/npm/d3-selection@3"></script>
+        <script src="https://cdn.jsdelivr.net/npm/d3-axis@3"></script>
         <script src="https://huww98.github.io/TimeChart/dist/timechart.min.js"></script>
         <style>
             #chart { width: 100%; height: 300px; margin-top: 300px; }
