diff --git a/Cargo.toml b/Cargo.toml
index c0ea8b0..49b88b3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,30 +29,30 @@ futures-lite = "1.11.0"
 once_cell = "1.4.1"
 
 [dev-dependencies]
-anyhow = "1.0.37"
-async-dup = "1.2.2"
-async-h1 = "2.3.0"
-async-native-tls = "0.3.3"
-async-tungstenite = { version = "0.13", features = ["async-native-tls"] }
-ctrlc = "3.1.6"
-doc-comment = "0.3.3"
-futures = "0.3.8"
-http = "0.2.2"
-http-types = "2.9.0"
-hyper = { version = "0.14.2", default-features = false, features = ["client", "http1", "server", "stream"] }
-native-tls = "0.2.7"
-scraper = "0.12.0"
-signal-hook = "0.3.2"
-surf = { version = "2.2", default-features = false, features = ["h1-client"] }
-tempfile = "3.2.0"
-tokio = { version = "1.0.1", default-features = false, features = ["rt-multi-thread"] }
-tungstenite = "0.13"
-url = "2.2.0"
+anyhow = "1"
+async-dup = "1"
+async-h1 = "2"
+async-native-tls = "0.4"
+async-tungstenite = { version = "0.16", features = ["async-native-tls"] }
+ctrlc = "3"
+doc-comment = "0.3"
+futures = "0.3"
+http = "0.2"
+http-types = "2"
+hyper = { version = "0.14", default-features = false, features = ["client", "http1", "server", "stream"] }
+native-tls = "0.2"
+scraper = "0.12"
+signal-hook = "0.3"
+surf = { version = "2", default-features = false, features = ["h1-client"] }
+tempfile = "3"
+tokio = { version = "1", default-features = false, features = ["rt-multi-thread"] }
+tungstenite = "0.16"
+url = "2"
 
 [target.'cfg(target_os = "linux")'.dev-dependencies]
-inotify = { version = "0.9.2", default-features = false }
-nix = "0.21"
-timerfd = "1.2.0"
+inotify = { version = "0.10", default-features = false }
+nix = "0.23"
+timerfd = "1"
 
 [target.'cfg(windows)'.dev-dependencies]
 uds_windows = "1"
diff --git a/examples/linux-timerfd.rs b/examples/linux-timerfd.rs
index f53335f..888c5f3 100644
--- a/examples/linux-timerfd.rs
+++ b/examples/linux-timerfd.rs
@@ -14,14 +14,6 @@ fn main() -> std::io::Result<()> {
     use smol::{io, Async};
     use timerfd::{SetTimeFlags, TimerFd, TimerState};
 
-    /// Converts a [`nix::Error`] into [`std::io::Error`].
-    fn io_err(err: nix::Error) -> io::Error {
-        match err {
-            nix::Error::Sys(code) => code.into(),
-            err => io::Error::new(io::ErrorKind::Other, Box::new(err)),
-        }
-    }
-
     /// Sleeps using an OS timer.
     async fn sleep(dur: Duration) -> io::Result<()> {
         // Create an OS timer.
@@ -30,7 +22,7 @@ fn main() -> std::io::Result<()> {
 
         // When the OS timer fires, a 64-bit integer can be read from it.
         Async::new(timer)?
-            .read_with(|t| nix::unistd::read(t.as_raw_fd(), &mut [0u8; 8]).map_err(io_err))
+            .read_with(|t| nix::unistd::read(t.as_raw_fd(), &mut [0u8; 8]).map_err(io::Error::from))
             .await?;
         Ok(())
     }