diff --git a/auxil/prometheus-cpp b/auxil/prometheus-cpp
index 4649065e2a..ad99e21f47 160000
--- a/auxil/prometheus-cpp
+++ b/auxil/prometheus-cpp
@@ -1 +1 @@
-Subproject commit 4649065e2a1dd21c81e41cd6007dce5486b77fc0
+Subproject commit ad99e21f4706193670c42b36c9824dc997f4c475