diff --git a/Cargo.toml b/Cargo.toml
index 62f39d1..ec2d94e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,7 +27,7 @@ features = ["derive"]
 [dev-dependencies]
 hex = "0.4"
 aws-config = { version = "<=1.1" }
-aws-smithy-runtime = { version = "<=1.2" }
+aws-smithy-runtime = { version = "<=1.6" }
 
 [features]
 default = ["key_openssl_pkey"]