diff --git a/Cargo.toml b/Cargo.toml
index 86f093b..f18312f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,7 +20,7 @@ default = ["async", "logging"]
 flume = { version = "0.11", default-features = false } # channel between threads
 if-addrs = { version = "0.10", features = ["link-local"] } # get local IP addresses
 log = { version = "0.4", optional = true }             # logging
-polling = "3.4.0"                                        # select/poll sockets
+polling = "2.1"                                        # select/poll sockets
 socket2 = { version = "0.5.5", features = ["all"] }      # socket APIs
 
 [dev-dependencies]
diff --git a/src/lib.rs b/src/lib.rs
index c6a2fe5..1039da5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -107,6 +107,7 @@
 //! - Only support multicast, not unicast send/recv.
 //! - Only support 32-bit or bigger platforms, not 16-bit platforms.
 
+#![forbid(unsafe_code)]
 #![allow(clippy::single_component_path_imports)]
 
 // log for logging (optional).
diff --git a/src/service_daemon.rs b/src/service_daemon.rs
index a2ddf02..ae23d35 100644
--- a/src/service_daemon.rs
+++ b/src/service_daemon.rs
@@ -85,7 +85,7 @@ pub enum UnregisterStatus {
 }
 
 /// Status code for the service daemon.
-#[derive(Debug, PartialEq, Clone, Eq)]
+#[derive(Debug, PartialEq, Clone)]
 #[non_exhaustive]
 pub enum DaemonStatus {
     /// The daemon is running as normal.
@@ -2305,9 +2305,9 @@ mod tests {
 
     #[test]
     fn test_instance_name() {
-        assert!(valid_instance_name("my-laser._printer._tcp.local."));
-        assert!(valid_instance_name("my-laser.._printer._tcp.local."));
-        assert!(!valid_instance_name("_printer._tcp.local."));
+        assert_eq!(valid_instance_name("my-laser._printer._tcp.local."), true);
+        assert_eq!(valid_instance_name("my-laser.._printer._tcp.local."), true);
+        assert_eq!(valid_instance_name("_printer._tcp.local."), false);
     }
 
     #[test]
diff --git a/src/service_info.rs b/src/service_info.rs
index d03acd3..be7ebea 100644
--- a/src/service_info.rs
+++ b/src/service_info.rs
@@ -743,7 +743,7 @@ mod tests {
 
         // test decode
         let decoded = decode_txt(&encoded);
-        assert!(properties[..] == decoded[..]);
+        assert!(&properties[..] == &decoded[..]);
 
         // test empty value
         let properties = vec![TxtProperty::from(&("key3", ""))];