diff --git a/i2c-vr/i2cvr_software_manager.cpp b/i2c-vr/i2cvr_software_manager.cpp
index 2c85da8..f1df77b 100644
--- a/i2c-vr/i2cvr_software_manager.cpp
+++ b/i2c-vr/i2cvr_software_manager.cpp
@@ -88,7 +88,7 @@
         co_return false;
     }
 
-    software->setVersion(std::to_string(sum));
+    software->setVersion(std::format("{:X}", sum));
 
     std::set<RequestedApplyTimes> allowedApplyTime = {
         RequestedApplyTimes::Immediate, RequestedApplyTimes::OnReset};