diff --git a/TestServer/packages.config b/TestServer/packages.config
index 6d037ac..8e0c2ae 100644
--- a/TestServer/packages.config
+++ b/TestServer/packages.config
@@ -6,7 +6,7 @@
   <package id="Microsoft.NETCore.Platforms" version="1.1.0" targetFramework="net452" />
   <package id="Microsoft.Win32.Primitives" version="4.3.0" targetFramework="net462" />
   <package id="NETStandard.Library" version="1.6.1" targetFramework="net452" />
-  <package id="PeterO.Cbor" version="3.0.3" targetFramework="net462" />
+  <package id="PeterO.Cbor" version="4.0.0" targetFramework="net462" />
   <package id="PeterO.Numbers" version="1.0.2" targetFramework="net462" />
   <package id="Portable.BouncyCastle" version="1.8.2" targetFramework="net462" />
   <package id="System.AppContext" version="4.3.0" targetFramework="net462" requireReinstallation="true" />