diff --git a/core/Cargo.toml b/core/Cargo.toml
index 9fdff3d5..78982b0f 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -63,7 +63,6 @@ runtime = [
 	"binary-merkle-tree",
 ]
 
-header-backward-compatibility-test = []
 try-runtime = [
 	"runtime",
 	"sp-runtime/try-runtime",
diff --git a/core/src/header/extension/mod.rs b/core/src/header/extension/mod.rs
index 31fa9a28..96f795cd 100644
--- a/core/src/header/extension/mod.rs
+++ b/core/src/header/extension/mod.rs
@@ -11,9 +11,6 @@ use crate::DataLookup;
 pub mod v1;
 pub mod v2;
 
-#[cfg(feature = "header-backward-compatibility-test")]
-pub mod v_test;
-
 /// Header extension data.
 #[derive(PartialEq, Eq, Clone, RuntimeDebug, TypeInfo, Encode, Decode)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
@@ -21,8 +18,6 @@ pub mod v_test;
 pub enum HeaderExtension {
 	V1(v1::HeaderExtension),
 	V2(v2::HeaderExtension),
-	#[cfg(feature = "header-backward-compatibility-test")]
-	VTest(v_test::HeaderExtension),
 }
 
 /// It forwards the call to the inner version of the header. Any invalid version will return the
@@ -32,8 +27,6 @@ macro_rules! forward_to_version {
 		match $self {
 			HeaderExtension::V1(ext) => ext.$function(),
 			HeaderExtension::V2(ext) => ext.$function(),
-			#[cfg(feature = "header-backward-compatibility-test")]
-			HeaderExtension::VTest(ext) => ext.$function(),
 		}
 	}};
 
@@ -41,8 +34,6 @@ macro_rules! forward_to_version {
 		match $self {
 			HeaderExtension::V1(ext) => ext.$function($arg),
 			HeaderExtension::V2(ext) => ext.$function($arg),
-			#[cfg(feature = "header-backward-compatibility-test")]
-			HeaderExtension::VTest(ext) => ext.$function($arg),
 		}
 	}};
 }
@@ -84,11 +75,3 @@ impl From<v2::HeaderExtension> for HeaderExtension {
 		Self::V2(ext)
 	}
 }
-
-#[cfg(feature = "header-backward-compatibility-test")]
-impl From<v_test::HeaderExtension> for HeaderExtension {
-	#[inline]
-	fn from(ext: v_test::HeaderExtension) -> Self {
-		Self::VTest(ext)
-	}
-}
diff --git a/core/src/header/extension/v_test.rs b/core/src/header/extension/v_test.rs
deleted file mode 100644
index ef859eea..00000000
--- a/core/src/header/extension/v_test.rs
+++ /dev/null
@@ -1,32 +0,0 @@
-use codec::{Decode, Encode};
-use scale_info::TypeInfo;
-#[cfg(feature = "serde")]
-use serde::{Deserialize, Serialize};
-use sp_core::{RuntimeDebug, H256};
-use sp_std::vec::Vec;
-
-use crate::{asdr::DataLookup, header::extension::v1, KateCommitment};
-
-#[derive(PartialEq, Eq, Clone, RuntimeDebug, TypeInfo, Encode, Decode, Default)]
-#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub struct HeaderExtension {
-	pub new_field: Vec<u8>,
-	pub commitment: KateCommitment,
-	pub app_lookup: DataLookup,
-}
-
-impl HeaderExtension {
-	pub fn data_root(&self) -> H256 {
-		self.commitment.data_root
-	}
-}
-
-impl From<v1::HeaderExtension> for HeaderExtension {
-	fn from(ext: v1::HeaderExtension) -> Self {
-		Self {
-			commitment: ext.commitment,
-			app_lookup: ext.app_lookup,
-			new_field: [1, 1, 2, 3, 5, 8, 13, 21, 34, 55].into(),
-		}
-	}
-}
diff --git a/core/src/header/mod.rs b/core/src/header/mod.rs
index 359b977c..876d852c 100644
--- a/core/src/header/mod.rs
+++ b/core/src/header/mod.rs
@@ -418,26 +418,8 @@ mod tests {
 		(encoded, error)
 	}
 
-	#[cfg(not(feature = "header-backward-compatibility-test"))]
-	fn header_test() -> THeader {
-		header_v1()
-	}
-
-	#[cfg(feature = "header-backward-compatibility-test")]
-	fn header_test() -> THeader {
-		let mut header = header_v1();
-		header.extension = extension::v_test::HeaderExtension {
-			new_field: b"New field for testing".to_vec(),
-			..Default::default()
-		}
-		.into();
-
-		header
-	}
-
 	#[test_case( header_v1().encode().as_ref() => Ok(header_v1()) ; "Decode V1 header")]
 	#[test_case( header_v2().encode().as_ref() => Ok(header_v2()) ; "Decode V2 header")]
-	#[test_case( header_test().encode().as_ref() => Ok(header_test()) ; "Decode test header")]
 	#[test_case( corrupted_header().0.as_ref() => Err(corrupted_header().1) ; "Decode corrupted header")]
 	fn header_decoding(mut encoded_header: &[u8]) -> Result<THeader, Error> {
 		Header::decode(&mut encoded_header)
@@ -448,7 +430,6 @@ mod tests {
 	}
 
 	#[test_case( header_serde_encode(header_v1()) => Ok(header_v1()) ; "Serde V1 header")]
-	#[test_case( header_serde_encode(header_test()) => Ok(header_test()) ; "Serde test header")]
 	fn header_serde(json_header: String) -> Result<THeader, String> {
 		serde_json::from_str(&json_header).map_err(|serde_err| format!("{}", serde_err))
 	}
@@ -514,8 +495,6 @@ mod tests {
 			extension::HeaderExtension::V2(ref mut ext) => {
 				ext.commitment.commitment = b"invalid commitment v2".to_vec();
 			},
-			#[cfg(feature = "header-backward-compatibility-test")]
-			_ => unreachable!(),
 		};
 
 		(header, hash)
@@ -531,8 +510,6 @@ mod tests {
 			extension::HeaderExtension::V2(ref mut ext) => {
 				ext.commitment.data_root = Some(H256::repeat_byte(2u8));
 			},
-			#[cfg(feature = "header-backward-compatibility-test")]
-			_ => unreachable!(),
 		};
 
 		(header, hash)
@@ -548,8 +525,6 @@ mod tests {
 			extension::HeaderExtension::V2(ref mut ext) => {
 				ext.commitment.cols += 2;
 			},
-			#[cfg(feature = "header-backward-compatibility-test")]
-			_ => unreachable!(),
 		};
 
 		(header, hash)
@@ -565,8 +540,6 @@ mod tests {
 			extension::HeaderExtension::V2(ref mut ext) => {
 				ext.commitment.rows += 2;
 			},
-			#[cfg(feature = "header-backward-compatibility-test")]
-			_ => unreachable!(),
 		};
 
 		(header, hash)
diff --git a/kate/Cargo.toml b/kate/Cargo.toml
index ccb981de..7950c354 100644
--- a/kate/Cargo.toml
+++ b/kate/Cargo.toml
@@ -12,7 +12,7 @@ license = "Apache-2.0"
 poly-multiproof = { git = "https://github.com/availproject/poly-multiproof", default-features = false, tag = "v0.0.1", optional = true }
 
 # Internal
-avail-core = { path = "../core", default-features = false, feature = "runtime" }
+avail-core = { path = "../core", default-features = false }
 kate-recovery = { path = "recovery", default-features = false }
 
 dusk-plonk = { git = "https://github.com/availproject/plonk.git", tag = "v0.12.0-polygon-2", optional = true }