diff --git a/src/cbor/tests/t_appendix_a.ml b/src/cbor/tests/t_appendix_a.ml
index 9124e739..7124ba7d 100644
--- a/src/cbor/tests/t_appendix_a.ml
+++ b/src/cbor/tests/t_appendix_a.ml
@@ -1,5 +1,5 @@
 
-let verbose = Sys.getenv_opt "VERBOSE"=Some "1"
+let verbose = try Sys.getenv "VERBOSE"="1" with _ -> false
 
 [@@@ifge 4.08]