diff --git a/Cargo.toml b/Cargo.toml
index 3bc03abb..38bd09c4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,25 +25,25 @@ all-features = true
 # <https://users.rust-lang.org/t/psa-please-specify-precise-dependency-versions-in-cargo-toml/71277>
 
 [dependencies]
-async-trait = "0.1.75"
+async-trait = "0.1.77"
 byteorder = "1.5.0"
 bytes = "1.5.0"
-futures = { version = "0.3.29", optional = true }
-futures-util = { version = "0.3.29", optional = true, default-features = false }
+futures-core = { version = "0.3.30", optional = true, default-features = false }
+futures-util = { version = "0.3.30", optional = true, default-features = false }
 log = "0.4.20"
-smallvec = { version = "1.11.2", default-features = false }
+smallvec = { version = "1.11.2", optional = true, default-features = false }
 socket2 = { version = "0.5.5", optional = true, default-features = false }
 tokio = { version = "1.35.1", default-features = false }
 # Disable default-features to exclude unused dependency on libudev
 tokio-serial = { version = "5.4.4", optional = true, default-features = false }
-tokio-util = { version = "0.7.10", default-features = false, features = [
+tokio-util = { version = "0.7.10", optional = true, default-features = false, features = [
     "codec",
 ] }
 
 [dev-dependencies]
-anyhow = "1.0.76"
+anyhow = "1.0.79"
 env_logger = "0.10.1"
-futures = "0.3.29"
+futures = "0.3.30"
 tokio = { version = "1.35.1", default-features = false, features = [
     "macros",
     "rt-multi-thread",
@@ -58,8 +58,13 @@ webpki = "0.22.4"
 
 [features]
 default = ["rtu", "tcp"]
-rtu = ["futures-util/sink"]
-tcp = ["tokio/net", "futures-util/sink"]
+rtu = [
+    "dep:futures-core",
+    "futures-util/sink",
+    "dep:smallvec",
+    "dep:tokio-util",
+]
+tcp = ["dep:futures-core", "futures-util/sink", "tokio/net", "dep:tokio-util"]
 rtu-sync = ["rtu", "sync", "dep:tokio-serial"]
 tcp-sync = ["tcp", "sync"]
 rtu-server = ["rtu", "server", "tokio/macros", "dep:tokio-serial"]
@@ -70,16 +75,10 @@ tcp-server = [
     "tokio/macros",
     "tokio/rt-multi-thread",
 ]
-rtu-over-tcp-server = [
-    "rtu",
-    "server",
-    "socket2/all",
-    "tokio/macros",
-    "tokio/rt-multi-thread",
-]
+rtu-over-tcp-server = ["rtu", "tcp-server"]
 # The following features are internal and must not be used in dependencies.
-sync = ["dep:futures", "tokio/time", "tokio/rt"]
-server = ["dep:futures"]
+sync = ["dep:futures-core", "futures-util/sink", "tokio/time", "tokio/rt"]
+server = []
 
 [badges]
 maintenance = { status = "actively-developed" }
diff --git a/examples/rtu-over-tcp-server.rs b/examples/rtu-over-tcp-server.rs
index 57f3aa02..5ab5fb96 100644
--- a/examples/rtu-over-tcp-server.rs
+++ b/examples/rtu-over-tcp-server.rs
@@ -8,12 +8,12 @@
 
 use std::{
     collections::HashMap,
+    future,
     net::SocketAddr,
     sync::{Arc, Mutex},
     time::Duration,
 };
 
-use futures::future;
 use tokio::net::TcpListener;
 
 use tokio_modbus::{
diff --git a/examples/rtu-server-address.rs b/examples/rtu-server-address.rs
index c83ee0ce..705b32bb 100644
--- a/examples/rtu-server-address.rs
+++ b/examples/rtu-server-address.rs
@@ -3,9 +3,7 @@
 
 //! RTU server example with slave address filtering and optional response
 
-use std::{thread, time::Duration};
-
-use futures::future;
+use std::{future, thread, time::Duration};
 
 use tokio_modbus::{prelude::*, server::rtu::Server};
 
diff --git a/examples/rtu-server.rs b/examples/rtu-server.rs
index 1fc1e0eb..0b943d62 100644
--- a/examples/rtu-server.rs
+++ b/examples/rtu-server.rs
@@ -3,9 +3,7 @@
 
 //! RTU server example
 
-use std::{thread, time::Duration};
-
-use futures::future;
+use std::{future, thread, time::Duration};
 
 use tokio_modbus::{prelude::*, server::rtu::Server};
 
diff --git a/examples/tcp-server.rs b/examples/tcp-server.rs
index ba9d8096..fc52a653 100644
--- a/examples/tcp-server.rs
+++ b/examples/tcp-server.rs
@@ -8,12 +8,12 @@
 
 use std::{
     collections::HashMap,
+    future,
     net::SocketAddr,
     sync::{Arc, Mutex},
     time::Duration,
 };
 
-use futures::future;
 use tokio::net::TcpListener;
 
 use tokio_modbus::{
diff --git a/examples/tls-server.rs b/examples/tls-server.rs
index f328497f..fc661a0b 100644
--- a/examples/tls-server.rs
+++ b/examples/tls-server.rs
@@ -9,6 +9,7 @@
 use std::{
     collections::HashMap,
     fs::File,
+    future,
     io::{self, BufReader},
     net::SocketAddr,
     path::Path,
@@ -16,7 +17,6 @@ use std::{
     time::Duration,
 };
 
-use futures::future;
 use pkcs8::der::Decode;
 use rustls_pemfile::{certs, pkcs8_private_keys};
 use tokio::net::{TcpListener, TcpStream};
diff --git a/src/client/sync/mod.rs b/src/client/sync/mod.rs
index 756403d2..d2898a80 100644
--- a/src/client/sync/mod.rs
+++ b/src/client/sync/mod.rs
@@ -11,7 +11,7 @@ pub mod tcp;
 
 use std::{future::Future, io::Result, time::Duration};
 
-use futures::future::Either;
+use futures_util::future::Either;
 
 use crate::{frame::*, slave::*};
 
diff --git a/src/frame/mod.rs b/src/frame/mod.rs
index 9e7b4e85..285014bc 100644
--- a/src/frame/mod.rs
+++ b/src/frame/mod.rs
@@ -443,11 +443,19 @@ impl From<Result<Response, ExceptionResponse>> for ResponsePdu {
     }
 }
 
-#[cfg(feature = "server")]
+#[cfg(any(
+    feature = "rtu-over-tcp-server",
+    feature = "rtu-server",
+    feature = "tcp-server"
+))]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct OptionalResponsePdu(pub(crate) Option<ResponsePdu>);
 
-#[cfg(feature = "server")]
+#[cfg(any(
+    feature = "rtu-over-tcp-server",
+    feature = "rtu-server",
+    feature = "tcp-server"
+))]
 impl<T> From<Option<T>> for OptionalResponsePdu
 where
     T: Into<ResponsePdu>,
@@ -457,7 +465,7 @@ where
     }
 }
 
-#[cfg(feature = "server")]
+#[cfg(any(feature = "rtu-server", feature = "tcp-server"))]
 impl<T> From<T> for OptionalResponsePdu
 where
     T: Into<ResponsePdu>,
diff --git a/src/server/rtu.rs b/src/server/rtu.rs
index 4a71b9cb..f2a50fec 100644
--- a/src/server/rtu.rs
+++ b/src/server/rtu.rs
@@ -3,10 +3,9 @@
 
 //! Modbus RTU server skeleton
 
-use std::{io, path::Path};
+use std::{future::Future, io, path::Path};
 
-use futures::{Future, FutureExt as _};
-use futures_util::{SinkExt as _, StreamExt as _};
+use futures_util::{FutureExt as _, SinkExt as _, StreamExt as _};
 use tokio_serial::SerialStream;
 use tokio_util::codec::Framed;
 
diff --git a/src/server/rtu_over_tcp.rs b/src/server/rtu_over_tcp.rs
index 088c3a58..ee25a94e 100644
--- a/src/server/rtu_over_tcp.rs
+++ b/src/server/rtu_over_tcp.rs
@@ -3,11 +3,10 @@
 
 //! Modbus RTU over TCP server skeleton
 
-use std::{io, net::SocketAddr};
+use std::{future::Future, io, net::SocketAddr};
 
 use async_trait::async_trait;
-use futures::{self, Future};
-use futures_util::{future::FutureExt as _, sink::SinkExt as _, stream::StreamExt as _};
+use futures_util::{FutureExt as _, SinkExt as _, StreamExt as _};
 use socket2::{Domain, Socket, Type};
 use tokio::{
     io::{AsyncRead, AsyncWrite},
diff --git a/src/server/tcp.rs b/src/server/tcp.rs
index dcdab17b..36a621b8 100644
--- a/src/server/tcp.rs
+++ b/src/server/tcp.rs
@@ -3,11 +3,10 @@
 
 //! Modbus TCP server skeleton
 
-use std::{io, net::SocketAddr};
+use std::{future::Future, io, net::SocketAddr};
 
 use async_trait::async_trait;
-use futures::{self, Future};
-use futures_util::{future::FutureExt as _, sink::SinkExt as _, stream::StreamExt as _};
+use futures_util::{FutureExt as _, SinkExt as _, StreamExt as _};
 use socket2::{Domain, Socket, Type};
 use tokio::{
     io::{AsyncRead, AsyncWrite},
@@ -211,9 +210,7 @@ mod tests {
 
     use crate::{prelude::*, server::Service};
 
-    use std::sync::Arc;
-
-    use futures::future;
+    use std::{future, sync::Arc};
 
     #[tokio::test]
     async fn delegate_service_through_deref_for_server() {
diff --git a/src/service/rtu.rs b/src/service/rtu.rs
index aae8d1ad..9c12cdde 100644
--- a/src/service/rtu.rs
+++ b/src/service/rtu.rs
@@ -6,7 +6,7 @@ use std::{
     io::{Error, ErrorKind},
 };
 
-use futures_util::{sink::SinkExt as _, stream::StreamExt as _};
+use futures_util::{SinkExt as _, StreamExt as _};
 use tokio::io::{AsyncRead, AsyncWrite};
 use tokio_util::codec::Framed;
 
diff --git a/src/service/tcp.rs b/src/service/tcp.rs
index f332d8ec..cb992f41 100644
--- a/src/service/tcp.rs
+++ b/src/service/tcp.rs
@@ -7,7 +7,7 @@ use std::{
     sync::atomic::{AtomicU16, Ordering},
 };
 
-use futures_util::{sink::SinkExt as _, stream::StreamExt as _};
+use futures_util::{SinkExt as _, StreamExt as _};
 use tokio::io::{AsyncRead, AsyncWrite};
 use tokio_util::codec::Framed;