diff --git a/Cargo.toml b/Cargo.toml
index e71a749..af09955 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "usbd-ethernet"
-version = "0.2.0"
+version = "0.3.0"
 edition = "2021"
 description = "Communication Device Class Network Control Model (CDC-NCM) class for usb-device"
 license = "MIT"
@@ -11,7 +11,7 @@ authors = ["Daniel Kenyon-Jones"]
 homepage = "https://github.com/dlkj/usbd-ethernet"
 
 [dependencies]
-smoltcp = { version = "0.11", default-features = false, features = [
+smoltcp = { version = "0.12", default-features = false, features = [
     "defmt",
     "proto-ipv4",
     "medium-ethernet",
diff --git a/examples/rp2040/Cargo.toml b/examples/rp2040/Cargo.toml
index 47896f7..24cb130 100644
--- a/examples/rp2040/Cargo.toml
+++ b/examples/rp2040/Cargo.toml
@@ -18,7 +18,7 @@ defmt = "0.3"
 defmt-rtt = "0.4"
 panic-probe = { version = "0.3", features = ["print-defmt"] }
 
-smoltcp = { version = "0.11", default-features = false, features = [
+smoltcp = { version = "0.12", default-features = false, features = [
     "defmt",
     "socket-tcp",
     "socket-dhcpv4",
diff --git a/examples/rp2040/src/main.rs b/examples/rp2040/src/main.rs
index abd4a89..0e28c9d 100644
--- a/examples/rp2040/src/main.rs
+++ b/examples/rp2040/src/main.rs
@@ -15,6 +15,7 @@ use hal::{clocks::init_clocks_and_plls, pac, watchdog::Watchdog};
 use heapless::Vec;
 use panic_probe as _;
 use rp_pico as bsp;
+use smoltcp::iface::PollResult;
 use smoltcp::socket::dhcpv4::RetryConfig;
 use smoltcp::time::Duration;
 use smoltcp::wire::DhcpOption;
@@ -148,7 +149,9 @@ fn main() -> ! {
             let timestamp =
                 Instant::from_micros(i64::try_from(timer.get_counter().ticks()).unwrap());
 
-            if interface.poll(timestamp, &mut ethernet, &mut sockets) {
+            if let PollResult::SocketStateChanged =
+                interface.poll(timestamp, &mut ethernet, &mut sockets)
+            {
                 dhcp_poll(
                     &mut interface,
                     sockets.get_mut::<dhcpv4::Socket>(dhcp_handle),
diff --git a/src/ethernet.rs b/src/ethernet.rs
index 217c703..c2f32e8 100644
--- a/src/ethernet.rs
+++ b/src/ethernet.rs
@@ -355,7 +355,7 @@ impl<B: UsbBus> OutBuf<'_, B> {
 
     fn read_datagram<R, F>(&mut self, f: F) -> Result<R>
     where
-        F: FnOnce(&mut [u8]) -> R,
+        F: FnOnce(&[u8]) -> R,
     {
         if !self.can_read() {
             return Err(UsbError::WouldBlock);
@@ -902,7 +902,7 @@ impl<'a, 'b, B: UsbBus> EthernetRxToken<'a, 'b, B> {
 impl<B: UsbBus> phy::RxToken for EthernetRxToken<'_, '_, B> {
     fn consume<R, F>(self, f: F) -> R
     where
-        F: FnOnce(&mut [u8]) -> R,
+        F: FnOnce(&[u8]) -> R,
     {
         self.ethernet.read_datagram(f).unwrap()
     }