diff --git a/core/Cargo.toml b/core/Cargo.toml
index c1f2044..bc4714a 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "bbqueue"
-version = "0.5.0"
+version = "0.5.1"
 description = "A SPSC, lockless, no_std, thread safe, queue, based on BipBuffers"
 repository = "https://github.com/jamesmunns/bbqueue"
 authors = ["James Munns <james.munns@ferrous-systems.com>"]
@@ -15,10 +15,15 @@ categories = [
 license = "MIT OR Apache-2.0"
 
 [dependencies]
-cortex-m = { version = "0.6.0", optional = true }
+cortex-m = { version = "0.7.0", optional = true }
+
+[dependencies.defmt]
+version = "0.3.0"
+optional = true
 
 [features]
 thumbv6 = ["cortex-m"]
+defmt_0_3 = ["defmt"]
 
 [package.metadata.docs.rs]
 all-features = true
diff --git a/core/src/lib.rs b/core/src/lib.rs
index ea2348d..49ee1bd 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -112,6 +112,7 @@ pub type Result<T> = CoreResult<T, Error>;
 
 /// Error type used by the `BBQueue` interfaces
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "defmt_0_3", derive(defmt::Format))]
 pub enum Error {
     /// The buffer does not contain sufficient size for the requested action
     InsufficientSize,