diff --git a/tokio-rustls/Cargo.toml b/tokio-rustls/Cargo.toml
index c20568c..618f72c 100644
--- a/tokio-rustls/Cargo.toml
+++ b/tokio-rustls/Cargo.toml
@@ -10,6 +10,7 @@ readme = "README.md"
 description = "Asynchronous TLS/SSL streams for Tokio using Rustls."
 categories = ["asynchronous", "cryptography", "network-programming"]
 edition = "2018"
+rust-version = "1.56"
 
 [dependencies]
 tokio = "1.0"
diff --git a/tokio-rustls/examples/client/Cargo.toml b/tokio-rustls/examples/client/Cargo.toml
index 4506cc9..3cefe18 100644
--- a/tokio-rustls/examples/client/Cargo.toml
+++ b/tokio-rustls/examples/client/Cargo.toml
@@ -3,10 +3,11 @@ name = "client"
 version = "0.1.0"
 authors = ["quininer <quininer@live.com>"]
 edition = "2018"
+rust-version = "1.56"
 
 [dependencies]
 tokio = { version = "1.0", features = [ "full" ] }
 argh = "0.1"
 tokio-rustls = { path = "../.." }
 webpki-roots = "0.22"
-rustls-pemfile = "0.2"
\ No newline at end of file
+rustls-pemfile = "0.2"
diff --git a/tokio-rustls/examples/server/Cargo.toml b/tokio-rustls/examples/server/Cargo.toml
index c563ed7..bdc3235 100644
--- a/tokio-rustls/examples/server/Cargo.toml
+++ b/tokio-rustls/examples/server/Cargo.toml
@@ -3,9 +3,10 @@ name = "server"
 version = "0.1.0"
 authors = ["quininer <quininer@live.com>"]
 edition = "2018"
+rust-version = "1.56"
 
 [dependencies]
 tokio = { version = "1.0", features = [ "full" ] }
 argh = "0.1"
 tokio-rustls = { path = "../.." }
-rustls-pemfile = "0.2.1"
\ No newline at end of file
+rustls-pemfile = "0.2.1"