diff --git a/floodsub/Cargo.toml b/floodsub/Cargo.toml
index b502b8f7..fd4481a5 100644
--- a/floodsub/Cargo.toml
+++ b/floodsub/Cargo.toml
@@ -14,7 +14,7 @@ libp2p-swarm = { path = "../swarm" }
 log = "0.4.1"
 multiaddr = "0.3"
 parking_lot = "0.5.3"
-protobuf = "1.4.2"
+protobuf = "=1.4.2"
 smallvec = "0.6.0"
 tokio-io = "0.1"
 varint = { path = "../varint-rs" }
diff --git a/identify/Cargo.toml b/identify/Cargo.toml
index b65c86a2..dc286b6d 100644
--- a/identify/Cargo.toml
+++ b/identify/Cargo.toml
@@ -10,7 +10,7 @@ libp2p-peerstore = { path = "../peerstore" }
 libp2p-swarm = { path = "../swarm" }
 log = "0.4.1"
 multiaddr = "0.3.0"
-protobuf = "1.4.2"
+protobuf = "=1.4.2"
 tokio-io = "0.1.0"
 varint = { path = "../varint-rs" }
 
diff --git a/kad/Cargo.toml b/kad/Cargo.toml
index 1926a71a..1539fbc3 100644
--- a/kad/Cargo.toml
+++ b/kad/Cargo.toml
@@ -18,7 +18,7 @@ libp2p-swarm = { path = "../swarm" }
 log = "0.4"
 multiaddr = "0.3"
 parking_lot = "0.5.1"
-protobuf = "1.4.2"
+protobuf = "=1.4.2"
 rand = "0.4.2"
 smallvec = "0.5"
 tokio-io = "0.1"
diff --git a/secio/Cargo.toml b/secio/Cargo.toml
index 2e761c0a..cebf11c5 100644
--- a/secio/Cargo.toml
+++ b/secio/Cargo.toml
@@ -8,7 +8,7 @@ bytes = "0.4"
 futures = "0.1"
 libp2p-swarm = { path = "../swarm" }
 log = "0.4.1"
-protobuf = "1.4.2"
+protobuf = "=1.4.2"
 rand = "0.3.17"
 ring = { version = "0.12.1", features = ["rsa_signing"] }
 rust-crypto = "^0.2"