diff --git a/bench/rpxy.toml b/bench/rpxy.toml
index d34150a..9eedbc8 100644
--- a/bench/rpxy.toml
+++ b/bench/rpxy.toml
@@ -1,7 +1,6 @@
 listen_port = 8080
 # listen_port_tls = 8443
 listen_ipv6 = false
-listen_only_ipv6 = false
 
 max_concurrent_streams = 128
 max_clients = 512
@@ -21,4 +20,4 @@ reverse_proxy = [
 
 
 [experimental]
-h3 = true
+h3 = false
diff --git a/config-example.toml b/config-example.toml
index 34830cc..5203cc0 100644
--- a/config-example.toml
+++ b/config-example.toml
@@ -16,7 +16,6 @@ max_clients = 512
 
 # Optional: Listen [::]
 listen_ipv6 = false
-listen_only_ipv6 = false
 
 # Optional: App that serves all plaintext http request by referring to HOSTS or request header
 # execpt for configured application.
@@ -45,7 +44,7 @@ reverse_proxy = [
   ] },
 ]
 # Optional: TLS setting. if https_port is specified and tls is true above, this must be given.
-tls = { https_redirection = true, tls_cert_path = '/tmp/localhost.pem', tls_cert_key_path = '/tmp/localhost.pem' }
+tls = { https_redirection = true, tls_cert_path = 'localhost.pem', tls_cert_key_path = 'localhost.pem' }
 
 
 ## List of destinations to send data to.
diff --git a/docker-compose.yml b/docker-compose.yml
index c7e0188..0cac872 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -12,5 +12,5 @@ services:
     tty: false
     privileged: true
     volumes:
-      - ./localhost.pem:/tmp/localhost.pem:ro
+      - ./example-certs:/tmp/certs:ro
       - ./config-example.toml:/etc/rpxy.toml:ro
diff --git a/src/config/parse.rs b/src/config/parse.rs
index 9bc6bad..a9e4022 100644
--- a/src/config/parse.rs
+++ b/src/config/parse.rs
@@ -39,20 +39,11 @@ pub fn parse_opts(globals: &mut Globals, backends: &mut Backends) -> Result<()>
     },
     anyhow!("Wrong port spec.")
   );
-  let mut listen_addresses: Vec<&str> = Vec::new();
-  if let Some(v) = config.listen_only_ipv6 {
-    if v {
-      listen_addresses.extend(LISTEN_ADDRESSES_V6.iter());
-    } else {
-      listen_addresses.extend(LISTEN_ADDRESSES_V4.iter());
-    }
-  } else if let Some(v) = config.listen_ipv6 {
-    listen_addresses.extend(LISTEN_ADDRESSES_V4.iter());
+  let mut listen_addresses: Vec<&str> = LISTEN_ADDRESSES_V4.to_vec();
+  if let Some(v) = config.listen_ipv6 {
     if v {
       listen_addresses.extend(LISTEN_ADDRESSES_V6.iter());
     }
-  } else {
-    listen_addresses.extend(LISTEN_ADDRESSES_V4.iter());
   }
   globals.listen_sockets = listen_addresses
     .iter()
diff --git a/src/config/toml.rs b/src/config/toml.rs
index 87fc8bb..9c6e945 100644
--- a/src/config/toml.rs
+++ b/src/config/toml.rs
@@ -8,7 +8,6 @@ pub struct ConfigToml {
   pub listen_port: Option<u16>,
   pub listen_port_tls: Option<u16>,
   pub listen_ipv6: Option<bool>,
-  pub listen_only_ipv6: Option<bool>,
   pub max_concurrent_streams: Option<u32>,
   pub max_clients: Option<u32>,
   pub apps: Option<Apps>,
diff --git a/src/main.rs b/src/main.rs
index be59bfc..dff5a69 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -69,7 +69,7 @@ fn main() {
       apps: HashMap::<String, Backend>::default(),
     };
 
-    let _ = parse_opts(&mut globals, &mut backends).expect("Invalid configuration");
+    parse_opts(&mut globals, &mut backends).expect("Invalid configuration");
 
     entrypoint(Arc::new(globals), Arc::new(backends))
       .await
diff --git a/src/proxy/proxy_handler.rs b/src/proxy/proxy_handler.rs
index 3a01f49..dcc73ef 100644
--- a/src/proxy/proxy_handler.rs
+++ b/src/proxy/proxy_handler.rs
@@ -249,7 +249,7 @@ fn remove_connection_header(headers: &mut HeaderMap) {
 }
 
 fn remove_hop_header(headers: &mut HeaderMap) {
-  let _ = HOP_HEADERS.iter().for_each(|key| {
+  HOP_HEADERS.iter().for_each(|key| {
     headers.remove(*key);
   });
 }
diff --git a/src/proxy/proxy_tls.rs b/src/proxy/proxy_tls.rs
index 79b027a..39fd1cb 100644
--- a/src/proxy/proxy_tls.rs
+++ b/src/proxy/proxy_tls.rs
@@ -19,7 +19,7 @@ where
         for (server_name, backend) in self.backends.apps.iter() {
           if backend.tls_cert_key_path.is_some() && backend.tls_cert_path.is_some() {
             if let Err(_e) = backend.update_server_config().await {
-              warn!("Failed to update certs for {}", server_name);
+              warn!("Failed to update certs for {}: {}", server_name, _e);
             }
           }
         }