diff --git a/rtic-sync/CHANGELOG.md b/rtic-sync/CHANGELOG.md
index b0632c31fe..135b17bd22 100644
--- a/rtic-sync/CHANGELOG.md
+++ b/rtic-sync/CHANGELOG.md
@@ -7,6 +7,14 @@ For each category, _Added_, _Changed_, _Fixed_ add new entries at the top!
 
 ## [Unreleased]
 
+### Changed
+
+- Unstable features are now stable, the feature flag `unstable` is removed.
+
+### Added
+
+- `defmt v0.3` derives added and forwarded to `embedded-hal(-x)` crates.
+
 ## v1.2.0 - 2024-01-10
 
 ### Changed
diff --git a/rtic-sync/Cargo.toml b/rtic-sync/Cargo.toml
index 7df193d1e3..8eb6901437 100644
--- a/rtic-sync/Cargo.toml
+++ b/rtic-sync/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rtic-sync"
-version = "1.2.0"
+version = "1.3.0"
 
 edition = "2021"
 authors = [
@@ -17,23 +17,21 @@ repository = "https://github.com/rtic-rs/rtic"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
-[package.metadata.docs.rs]
-features = ["unstable"]
-
 [dependencies]
 heapless = "0.8"
 critical-section = "1"
 rtic-common = { version = "1.0.0", path = "../rtic-common" }
 portable-atomic = { version = "1", default-features = false }
-embedded-hal = { version = "1.0", optional = true }
-embedded-hal-async = { version = "1.0", optional = true }
-embedded-hal-bus = { version = "0.1.0", optional = true, features = ["async"] }
+embedded-hal = { version = "1.0.0" }
+embedded-hal-async = { version = "1.0.0" }
+embedded-hal-bus = { version = "0.1.0", features = ["async"] }
+
+defmt-03 = { package = "defmt", version = "0.3", optional = true }
 
 [dev-dependencies]
 tokio = { version = "1", features = ["rt", "macros", "time"] }
 
-
 [features]
 default = []
 testing = ["critical-section/std", "rtic-common/testing"]
-unstable = ["embedded-hal", "embedded-hal-async", "embedded-hal-bus"]
+defmt-03 = ["dep:defmt-03", "embedded-hal/defmt-03", "embedded-hal-async/defmt-03", "embedded-hal-bus/defmt-03"]
\ No newline at end of file
diff --git a/rtic-sync/src/arbiter.rs b/rtic-sync/src/arbiter.rs
index f0dbc4cdb3..b17fa00cfb 100644
--- a/rtic-sync/src/arbiter.rs
+++ b/rtic-sync/src/arbiter.rs
@@ -191,7 +191,6 @@ impl<'a, T> DerefMut for ExclusiveAccess<'a, T> {
     }
 }
 
-#[cfg(feature = "unstable")]
 /// SPI bus sharing using [`Arbiter`]
 pub mod spi {
     use super::Arbiter;
@@ -274,7 +273,6 @@ pub mod spi {
     }
 }
 
-#[cfg(feature = "unstable")]
 /// I2C bus sharing using [`Arbiter`]
 ///
 /// An Example how to use it in RTIC application:
diff --git a/rtic-sync/src/channel.rs b/rtic-sync/src/channel.rs
index 4f4f0c20ba..64d09d1114 100644
--- a/rtic-sync/src/channel.rs
+++ b/rtic-sync/src/channel.rs
@@ -18,6 +18,9 @@ use rtic_common::{
     wait_queue::{Link, WaitQueue},
 };
 
+#[cfg(feature = "defmt-03")]
+use crate::defmt;
+
 /// An MPSC channel for use in no-alloc systems. `N` sets the size of the queue.
 ///
 /// This channel uses critical sections, however there are extremely small and all `memcpy`
@@ -127,9 +130,11 @@ macro_rules! make_channel {
 // -------- Sender
 
 /// Error state for when the receiver has been dropped.
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub struct NoReceiver<T>(pub T);
 
 /// Errors that 'try_send` can have.
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub enum TrySendError<T> {
     /// Error state for when the receiver has been dropped.
     NoReceiver(T),
@@ -199,6 +204,13 @@ impl<'a, T, const N: usize> core::fmt::Debug for Sender<'a, T, N> {
     }
 }
 
+#[cfg(feature = "defmt-03")]
+impl<'a, T, const N: usize> defmt::Format for Sender<'a, T, N> {
+    fn format(&self, f: defmt::Formatter) {
+        defmt::write!(f, "Sender",)
+    }
+}
+
 impl<'a, T, const N: usize> Sender<'a, T, N> {
     #[inline(always)]
     fn send_footer(&mut self, idx: u8, val: T) {
@@ -382,8 +394,16 @@ impl<'a, T, const N: usize> core::fmt::Debug for Receiver<'a, T, N> {
     }
 }
 
+#[cfg(feature = "defmt-03")]
+impl<'a, T, const N: usize> defmt::Format for Receiver<'a, T, N> {
+    fn format(&self, f: defmt::Formatter) {
+        defmt::write!(f, "Receiver",)
+    }
+}
+
 /// Possible receive errors.
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub enum ReceiveError {
     /// Error state for when all senders has been dropped.
     NoSender,
diff --git a/rtic-sync/src/lib.rs b/rtic-sync/src/lib.rs
index ecd3247d5a..90afff63b3 100644
--- a/rtic-sync/src/lib.rs
+++ b/rtic-sync/src/lib.rs
@@ -3,6 +3,9 @@
 #![no_std]
 #![deny(missing_docs)]
 
+#[cfg(feature = "defmt-03")]
+use defmt_03 as defmt;
+
 pub mod arbiter;
 pub mod channel;
 pub use portable_atomic;
diff --git a/xtask/src/argument_parsing.rs b/xtask/src/argument_parsing.rs
index 5d9c00e549..3893c610ea 100644
--- a/xtask/src/argument_parsing.rs
+++ b/xtask/src/argument_parsing.rs
@@ -90,7 +90,6 @@ impl Package {
                     .chain(std::iter::once(None))
                     .collect()
             }
-            Package::RticSync => vec![Some("unstable".to_string()), None],
             _ => vec![None],
         }
     }