diff --git a/amadeus-postgres/Cargo.toml b/amadeus-postgres/Cargo.toml
index 08521e7b..9aa3b223 100644
--- a/amadeus-postgres/Cargo.toml
+++ b/amadeus-postgres/Cargo.toml
@@ -29,7 +29,7 @@ pin-project = "0.4"
 postgres = { package = "tokio-postgres", version = "0.5", features = ["with-chrono-0_4"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_closure = "0.3"
-sum = "0.1"
+sum = { version = "0.1.7", default-features = false }
 tokio = "0.2"
 
 [build-dependencies]
diff --git a/amadeus-serde/Cargo.toml b/amadeus-serde/Cargo.toml
index 56ca82a5..2b86f0d3 100644
--- a/amadeus-serde/Cargo.toml
+++ b/amadeus-serde/Cargo.toml
@@ -30,7 +30,7 @@ serde = { version = "1.0", features = ["derive"] }
 serde_bytes = "0.11"
 serde_closure = "0.3"
 serde_json = "1.0"
-sum = { version = "0.1", features = ["serde"] }
+sum = { version = "0.1.7", default-features = false, features = ["serde"] }
 recycle = "0.1"
 
 [build-dependencies]