diff --git a/bridges/primitives/polkadot-core/src/lib.rs b/bridges/primitives/polkadot-core/src/lib.rs
index 4744e29492..ab4e0f5947 100644
--- a/bridges/primitives/polkadot-core/src/lib.rs
+++ b/bridges/primitives/polkadot-core/src/lib.rs
@@ -235,26 +235,26 @@ impl<Call> parity_scale_codec::Decode for SignedExtensions<Call> {
 impl<Call> SignedExtensions<Call> {
 	pub fn new(
 		version: sp_version::RuntimeVersion,
-		era: sp_runtime::generic::Era,
+		era: bp_runtime::TransactionEraOf<PolkadotLike>,
 		genesis_hash: Hash,
 		nonce: Nonce,
 		tip: Balance,
 	) -> Self {
 		Self {
 			encode_payload: (
-				(),           // spec version
-				(),           // tx version
-				(),           // genesis
-				era,          // era
-				nonce.into(), // nonce (compact encoding)
-				(),           // Check weight
-				tip.into(),   // transaction payment / tip (compact encoding)
+				(),              // spec version
+				(),              // tx version
+				(),              // genesis
+				era.frame_era(), // era
+				nonce.into(),    // nonce (compact encoding)
+				(),              // Check weight
+				tip.into(),      // transaction payment / tip (compact encoding)
 			),
 			additional_signed: (
 				version.spec_version,
 				version.transaction_version,
 				genesis_hash,
-				genesis_hash,
+				era.signed_payload(genesis_hash),
 				(),
 				(),
 				(),
diff --git a/bridges/primitives/runtime/src/chain.rs b/bridges/primitives/runtime/src/chain.rs
index cb19c6e726..270e2d7b2f 100644
--- a/bridges/primitives/runtime/src/chain.rs
+++ b/bridges/primitives/runtime/src/chain.rs
@@ -42,7 +42,10 @@ pub trait Chain: Send + Sync + 'static {
 		+ FromStr
 		+ MaybeMallocSizeOf
 		+ AsPrimitive<usize>
-		+ Default;
+		+ Default
+		// original `sp_runtime::traits::Header::BlockNumber` doesn't have this trait, but
+		// `sp_runtime::generic::Era` requires block number -> `u64` conversion.
+		+ Into<u64>;
 
 	/// A type that fulfills the abstract idea of what a Substrate hash is.
 	// Constraits come from the associated Hash type of `sp_runtime::traits::Header`
@@ -85,3 +88,6 @@ pub type HasherOf<C> = <C as Chain>::Hasher;
 
 /// Header type used by the chain.
 pub type HeaderOf<C> = <C as Chain>::Header;
+
+/// Transaction era used by the chain.
+pub type TransactionEraOf<C> = crate::TransactionEra<BlockNumberOf<C>, HashOf<C>>;
diff --git a/bridges/primitives/runtime/src/lib.rs b/bridges/primitives/runtime/src/lib.rs
index ed915b7288..fa1586c792 100644
--- a/bridges/primitives/runtime/src/lib.rs
+++ b/bridges/primitives/runtime/src/lib.rs
@@ -19,11 +19,12 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use codec::Encode;
+use frame_support::RuntimeDebug;
 use sp_core::hash::H256;
 use sp_io::hashing::blake2_256;
 use sp_std::convert::TryFrom;
 
-pub use chain::{BlockNumberOf, Chain, HashOf, HasherOf, HeaderOf};
+pub use chain::{BlockNumberOf, Chain, HashOf, HasherOf, HeaderOf, TransactionEraOf};
 pub use storage_proof::{Error as StorageProofError, StorageProofChecker};
 
 #[cfg(feature = "std")]
@@ -138,3 +139,44 @@ impl Size for PreComputedSize {
 		u32::try_from(self.0).unwrap_or(u32::MAX)
 	}
 }
+
+/// Era of specific transaction.
+#[derive(RuntimeDebug, Clone, Copy)]
+pub enum TransactionEra<BlockNumber, BlockHash> {
+	/// Transaction is immortal.
+	Immortal,
+	/// Transaction is valid for given number of blocks, starting from given block.
+	Mortal(BlockNumber, BlockHash, u32),
+}
+
+impl<BlockNumber: Copy + Into<u64>, BlockHash: Copy> TransactionEra<BlockNumber, BlockHash> {
+	/// Prepare transaction era, based on mortality period and current best block number.
+	pub fn new(best_block_number: BlockNumber, best_block_hash: BlockHash, mortality_period: Option<u32>) -> Self {
+		mortality_period
+			.map(|mortality_period| TransactionEra::Mortal(best_block_number, best_block_hash, mortality_period))
+			.unwrap_or(TransactionEra::Immortal)
+	}
+
+	/// Create new immortal transaction era.
+	pub fn immortal() -> Self {
+		TransactionEra::Immortal
+	}
+
+	/// Returns era that is used by FRAME-based runtimes.
+	pub fn frame_era(&self) -> sp_runtime::generic::Era {
+		match *self {
+			TransactionEra::Immortal => sp_runtime::generic::Era::immortal(),
+			TransactionEra::Mortal(header_number, _, period) => {
+				sp_runtime::generic::Era::mortal(period as _, header_number.into())
+			}
+		}
+	}
+
+	/// Returns header hash that needs to be included in the signature payload.
+	pub fn signed_payload(&self, genesis_hash: BlockHash) -> BlockHash {
+		match *self {
+			TransactionEra::Immortal => genesis_hash,
+			TransactionEra::Mortal(_, header_hash, _) => header_hash,
+		}
+	}
+}
diff --git a/bridges/relays/bin-ethereum/src/rialto_client.rs b/bridges/relays/bin-ethereum/src/rialto_client.rs
index 311bc9edbc..b340c4d82a 100644
--- a/bridges/relays/bin-ethereum/src/rialto_client.rs
+++ b/bridges/relays/bin-ethereum/src/rialto_client.rs
@@ -157,11 +157,12 @@ impl SubmitEthereumHeaders for SubstrateClient<Rialto> {
 		let ids = headers.iter().map(|header| header.id()).collect();
 		let genesis_hash = *self.genesis_hash();
 		let submission_result = async {
-			self.submit_signed_extrinsic((*params.public().as_array_ref()).into(), move |transaction_nonce| {
+			self.submit_signed_extrinsic((*params.public().as_array_ref()).into(), move |_, transaction_nonce| {
 				Bytes(
 					Rialto::sign_transaction(
 						genesis_hash,
 						&params,
+						relay_substrate_client::TransactionEra::immortal(),
 						transaction_nonce,
 						instance.build_signed_header_call(headers),
 					)
@@ -259,11 +260,12 @@ impl SubmitEthereumExchangeTransactionProof for SubstrateClient<Rialto> {
 		proof: rialto_runtime::exchange::EthereumTransactionInclusionProof,
 	) -> RpcResult<()> {
 		let genesis_hash = *self.genesis_hash();
-		self.submit_signed_extrinsic((*params.public().as_array_ref()).into(), move |transaction_nonce| {
+		self.submit_signed_extrinsic((*params.public().as_array_ref()).into(), move |_, transaction_nonce| {
 			Bytes(
 				Rialto::sign_transaction(
 					genesis_hash,
 					&params,
+					relay_substrate_client::TransactionEra::immortal(),
 					transaction_nonce,
 					instance.build_currency_exchange_call(proof),
 				)
diff --git a/bridges/relays/bin-substrate/src/chains/millau_headers_to_rialto.rs b/bridges/relays/bin-substrate/src/chains/millau_headers_to_rialto.rs
index 5be5083f5b..75d7b49c40 100644
--- a/bridges/relays/bin-substrate/src/chains/millau_headers_to_rialto.rs
+++ b/bridges/relays/bin-substrate/src/chains/millau_headers_to_rialto.rs
@@ -54,6 +54,7 @@ impl SubstrateFinalitySyncPipeline for MillauFinalityToRialto {
 
 	fn make_submit_finality_proof_transaction(
 		&self,
+		era: bp_runtime::TransactionEraOf<Rialto>,
 		transaction_nonce: <Rialto as Chain>::Index,
 		header: MillauSyncHeader,
 		proof: GrandpaJustification<bp_millau::Header>,
@@ -64,6 +65,7 @@ impl SubstrateFinalitySyncPipeline for MillauFinalityToRialto {
 		let transaction = Rialto::sign_transaction(
 			genesis_hash,
 			&self.finality_pipeline.target_sign,
+			era,
 			transaction_nonce,
 			call,
 		);
diff --git a/bridges/relays/bin-substrate/src/chains/millau_messages_to_rialto.rs b/bridges/relays/bin-substrate/src/chains/millau_messages_to_rialto.rs
index b63d57aeb7..6fbce3d314 100644
--- a/bridges/relays/bin-substrate/src/chains/millau_messages_to_rialto.rs
+++ b/bridges/relays/bin-substrate/src/chains/millau_messages_to_rialto.rs
@@ -82,8 +82,13 @@ impl SubstrateMessageLane for MillauMessagesToRialto {
 			millau_runtime::MessagesCall::receive_messages_delivery_proof(proof, relayers_state).into();
 		let call_weight = call.get_dispatch_info().weight;
 		let genesis_hash = *self.message_lane.source_client.genesis_hash();
-		let transaction =
-			Millau::sign_transaction(genesis_hash, &self.message_lane.source_sign, transaction_nonce, call);
+		let transaction = Millau::sign_transaction(
+			genesis_hash,
+			&self.message_lane.source_sign,
+			relay_substrate_client::TransactionEra::immortal(),
+			transaction_nonce,
+			call,
+		);
 		log::trace!(
 			target: "bridge",
 			"Prepared Rialto -> Millau confirmation transaction. Weight: {}/{}, size: {}/{}",
@@ -122,8 +127,13 @@ impl SubstrateMessageLane for MillauMessagesToRialto {
 		.into();
 		let call_weight = call.get_dispatch_info().weight;
 		let genesis_hash = *self.message_lane.target_client.genesis_hash();
-		let transaction =
-			Rialto::sign_transaction(genesis_hash, &self.message_lane.target_sign, transaction_nonce, call);
+		let transaction = Rialto::sign_transaction(
+			genesis_hash,
+			&self.message_lane.target_sign,
+			relay_substrate_client::TransactionEra::immortal(),
+			transaction_nonce,
+			call,
+		);
 		log::trace!(
 			target: "bridge",
 			"Prepared Millau -> Rialto delivery transaction. Weight: {}/{}, size: {}/{}",
diff --git a/bridges/relays/bin-substrate/src/chains/mod.rs b/bridges/relays/bin-substrate/src/chains/mod.rs
index 8a9cb780b4..0d655698c5 100644
--- a/bridges/relays/bin-substrate/src/chains/mod.rs
+++ b/bridges/relays/bin-substrate/src/chains/mod.rs
@@ -214,6 +214,7 @@ mod tests {
 		let rialto_tx = Rialto::sign_transaction(
 			Default::default(),
 			&sp_keyring::AccountKeyring::Alice.pair(),
+			relay_substrate_client::TransactionEra::immortal(),
 			0,
 			rialto_call.clone(),
 		);
@@ -232,6 +233,7 @@ mod tests {
 		let millau_tx = Millau::sign_transaction(
 			Default::default(),
 			&sp_keyring::AccountKeyring::Alice.pair(),
+			relay_substrate_client::TransactionEra::immortal(),
 			0,
 			millau_call.clone(),
 		);
diff --git a/bridges/relays/bin-substrate/src/chains/rialto_headers_to_millau.rs b/bridges/relays/bin-substrate/src/chains/rialto_headers_to_millau.rs
index 2604e79983..69b750c542 100644
--- a/bridges/relays/bin-substrate/src/chains/rialto_headers_to_millau.rs
+++ b/bridges/relays/bin-substrate/src/chains/rialto_headers_to_millau.rs
@@ -55,6 +55,7 @@ impl SubstrateFinalitySyncPipeline for RialtoFinalityToMillau {
 
 	fn make_submit_finality_proof_transaction(
 		&self,
+		era: bp_runtime::TransactionEraOf<Millau>,
 		transaction_nonce: <Millau as Chain>::Index,
 		header: RialtoSyncHeader,
 		proof: GrandpaJustification<bp_rialto::Header>,
@@ -69,6 +70,7 @@ impl SubstrateFinalitySyncPipeline for RialtoFinalityToMillau {
 		let transaction = Millau::sign_transaction(
 			genesis_hash,
 			&self.finality_pipeline.target_sign,
+			era,
 			transaction_nonce,
 			call,
 		);
diff --git a/bridges/relays/bin-substrate/src/chains/rialto_messages_to_millau.rs b/bridges/relays/bin-substrate/src/chains/rialto_messages_to_millau.rs
index 1f861d1bb5..986b7519e1 100644
--- a/bridges/relays/bin-substrate/src/chains/rialto_messages_to_millau.rs
+++ b/bridges/relays/bin-substrate/src/chains/rialto_messages_to_millau.rs
@@ -82,8 +82,13 @@ impl SubstrateMessageLane for RialtoMessagesToMillau {
 			rialto_runtime::MessagesCall::receive_messages_delivery_proof(proof, relayers_state).into();
 		let call_weight = call.get_dispatch_info().weight;
 		let genesis_hash = *self.message_lane.source_client.genesis_hash();
-		let transaction =
-			Rialto::sign_transaction(genesis_hash, &self.message_lane.source_sign, transaction_nonce, call);
+		let transaction = Rialto::sign_transaction(
+			genesis_hash,
+			&self.message_lane.source_sign,
+			relay_substrate_client::TransactionEra::immortal(),
+			transaction_nonce,
+			call,
+		);
 		log::trace!(
 			target: "bridge",
 			"Prepared Millau -> Rialto confirmation transaction. Weight: {}/{}, size: {}/{}",
@@ -122,8 +127,13 @@ impl SubstrateMessageLane for RialtoMessagesToMillau {
 		.into();
 		let call_weight = call.get_dispatch_info().weight;
 		let genesis_hash = *self.message_lane.target_client.genesis_hash();
-		let transaction =
-			Millau::sign_transaction(genesis_hash, &self.message_lane.target_sign, transaction_nonce, call);
+		let transaction = Millau::sign_transaction(
+			genesis_hash,
+			&self.message_lane.target_sign,
+			relay_substrate_client::TransactionEra::immortal(),
+			transaction_nonce,
+			call,
+		);
 		log::trace!(
 			target: "bridge",
 			"Prepared Rialto -> Millau delivery transaction. Weight: {}/{}, size: {}/{}",
diff --git a/bridges/relays/bin-substrate/src/chains/rococo_headers_to_wococo.rs b/bridges/relays/bin-substrate/src/chains/rococo_headers_to_wococo.rs
index 38bb54ddbc..3cacce9a48 100644
--- a/bridges/relays/bin-substrate/src/chains/rococo_headers_to_wococo.rs
+++ b/bridges/relays/bin-substrate/src/chains/rococo_headers_to_wococo.rs
@@ -77,6 +77,7 @@ impl SubstrateFinalitySyncPipeline for RococoFinalityToWococo {
 
 	fn make_submit_finality_proof_transaction(
 		&self,
+		era: bp_runtime::TransactionEraOf<Wococo>,
 		transaction_nonce: <Wococo as Chain>::Index,
 		header: RococoSyncHeader,
 		proof: GrandpaJustification<bp_rococo::Header>,
@@ -88,6 +89,7 @@ impl SubstrateFinalitySyncPipeline for RococoFinalityToWococo {
 		let transaction = Wococo::sign_transaction(
 			genesis_hash,
 			&self.finality_pipeline.target_sign,
+			era,
 			transaction_nonce,
 			call,
 		);
diff --git a/bridges/relays/bin-substrate/src/chains/rococo_messages_to_wococo.rs b/bridges/relays/bin-substrate/src/chains/rococo_messages_to_wococo.rs
index 3abedc0ca3..7cc4d0f725 100644
--- a/bridges/relays/bin-substrate/src/chains/rococo_messages_to_wococo.rs
+++ b/bridges/relays/bin-substrate/src/chains/rococo_messages_to_wococo.rs
@@ -84,8 +84,13 @@ impl SubstrateMessageLane for RococoMessagesToWococo {
 			),
 		);
 		let genesis_hash = *self.message_lane.source_client.genesis_hash();
-		let transaction =
-			Rococo::sign_transaction(genesis_hash, &self.message_lane.source_sign, transaction_nonce, call);
+		let transaction = Rococo::sign_transaction(
+			genesis_hash,
+			&self.message_lane.source_sign,
+			relay_substrate_client::TransactionEra::immortal(),
+			transaction_nonce,
+			call,
+		);
 		log::trace!(
 			target: "bridge",
 			"Prepared Wococo -> Rococo confirmation transaction. Weight: <unknown>/{}, size: {}/{}",
@@ -124,8 +129,13 @@ impl SubstrateMessageLane for RococoMessagesToWococo {
 			),
 		);
 		let genesis_hash = *self.message_lane.target_client.genesis_hash();
-		let transaction =
-			Wococo::sign_transaction(genesis_hash, &self.message_lane.target_sign, transaction_nonce, call);
+		let transaction = Wococo::sign_transaction(
+			genesis_hash,
+			&self.message_lane.target_sign,
+			relay_substrate_client::TransactionEra::immortal(),
+			transaction_nonce,
+			call,
+		);
 		log::trace!(
 			target: "bridge",
 			"Prepared Rococo -> Wococo delivery transaction. Weight: <unknown>/{}, size: {}/{}",
diff --git a/bridges/relays/bin-substrate/src/chains/westend_headers_to_millau.rs b/bridges/relays/bin-substrate/src/chains/westend_headers_to_millau.rs
index 9fdf8b1a81..20464b99bf 100644
--- a/bridges/relays/bin-substrate/src/chains/westend_headers_to_millau.rs
+++ b/bridges/relays/bin-substrate/src/chains/westend_headers_to_millau.rs
@@ -63,6 +63,7 @@ impl SubstrateFinalitySyncPipeline for WestendFinalityToMillau {
 
 	fn make_submit_finality_proof_transaction(
 		&self,
+		era: bp_runtime::TransactionEraOf<Millau>,
 		transaction_nonce: <Millau as Chain>::Index,
 		header: WestendSyncHeader,
 		proof: GrandpaJustification<bp_westend::Header>,
@@ -77,6 +78,7 @@ impl SubstrateFinalitySyncPipeline for WestendFinalityToMillau {
 		let transaction = Millau::sign_transaction(
 			genesis_hash,
 			&self.finality_pipeline.target_sign,
+			era,
 			transaction_nonce,
 			call,
 		);
diff --git a/bridges/relays/bin-substrate/src/chains/wococo_headers_to_rococo.rs b/bridges/relays/bin-substrate/src/chains/wococo_headers_to_rococo.rs
index a65bfd7624..4bb5b15fe0 100644
--- a/bridges/relays/bin-substrate/src/chains/wococo_headers_to_rococo.rs
+++ b/bridges/relays/bin-substrate/src/chains/wococo_headers_to_rococo.rs
@@ -82,6 +82,7 @@ impl SubstrateFinalitySyncPipeline for WococoFinalityToRococo {
 
 	fn make_submit_finality_proof_transaction(
 		&self,
+		era: bp_runtime::TransactionEraOf<Rococo>,
 		transaction_nonce: <Rococo as Chain>::Index,
 		header: WococoSyncHeader,
 		proof: GrandpaJustification<bp_wococo::Header>,
@@ -93,6 +94,7 @@ impl SubstrateFinalitySyncPipeline for WococoFinalityToRococo {
 		let transaction = Rococo::sign_transaction(
 			genesis_hash,
 			&self.finality_pipeline.target_sign,
+			era,
 			transaction_nonce,
 			call,
 		);
diff --git a/bridges/relays/bin-substrate/src/chains/wococo_messages_to_rococo.rs b/bridges/relays/bin-substrate/src/chains/wococo_messages_to_rococo.rs
index d4cff289e2..16a8858ac9 100644
--- a/bridges/relays/bin-substrate/src/chains/wococo_messages_to_rococo.rs
+++ b/bridges/relays/bin-substrate/src/chains/wococo_messages_to_rococo.rs
@@ -83,8 +83,13 @@ impl SubstrateMessageLane for WococoMessagesToRococo {
 			),
 		);
 		let genesis_hash = *self.message_lane.source_client.genesis_hash();
-		let transaction =
-			Wococo::sign_transaction(genesis_hash, &self.message_lane.source_sign, transaction_nonce, call);
+		let transaction = Wococo::sign_transaction(
+			genesis_hash,
+			&self.message_lane.source_sign,
+			relay_substrate_client::TransactionEra::immortal(),
+			transaction_nonce,
+			call,
+		);
 		log::trace!(
 			target: "bridge",
 			"Prepared Rococo -> Wococo confirmation transaction. Weight: <unknown>/{}, size: {}/{}",
@@ -123,8 +128,13 @@ impl SubstrateMessageLane for WococoMessagesToRococo {
 			),
 		);
 		let genesis_hash = *self.message_lane.target_client.genesis_hash();
-		let transaction =
-			Rococo::sign_transaction(genesis_hash, &self.message_lane.target_sign, transaction_nonce, call);
+		let transaction = Rococo::sign_transaction(
+			genesis_hash,
+			&self.message_lane.target_sign,
+			relay_substrate_client::TransactionEra::immortal(),
+			transaction_nonce,
+			call,
+		);
 		log::trace!(
 			target: "bridge",
 			"Prepared Wococo -> Rococo delivery transaction. Weight: <unknown>/{}, size: {}/{}",
diff --git a/bridges/relays/bin-substrate/src/cli/init_bridge.rs b/bridges/relays/bin-substrate/src/cli/init_bridge.rs
index 846d3a575e..76bc5aa273 100644
--- a/bridges/relays/bin-substrate/src/cli/init_bridge.rs
+++ b/bridges/relays/bin-substrate/src/cli/init_bridge.rs
@@ -150,6 +150,7 @@ impl InitBridge {
 						Target::sign_transaction(
 							*target_client.genesis_hash(),
 							&target_sign,
+							relay_substrate_client::TransactionEra::immortal(),
 							transaction_nonce,
 							encode_init_bridge(initialization_data),
 						)
diff --git a/bridges/relays/bin-substrate/src/cli/mod.rs b/bridges/relays/bin-substrate/src/cli/mod.rs
index 832b530877..c02f6b5130 100644
--- a/bridges/relays/bin-substrate/src/cli/mod.rs
+++ b/bridges/relays/bin-substrate/src/cli/mod.rs
@@ -389,6 +389,10 @@ macro_rules! declare_chain_options {
 				#[doc = "Path to the file, that password for the SURI of secret key to use when transactions are submitted to the " $chain " node. Can be overridden with " $chain_prefix "_signer_password option."]
 				#[structopt(long)]
 				pub [<$chain_prefix _signer_password_file>]: Option<std::path::PathBuf>,
+
+				#[doc = "Transactions mortality period, in blocks. MUST be a power of two in [4; 65536] range. MAY NOT be larger than `BlockHashCount` parameter of the chain system module."]
+				#[structopt(long)]
+				pub [<$chain_prefix _transactions_mortality>]: Option<u32>,
 			}
 
 			#[doc = "Parameters required to sign transaction on behalf of owner of the messages pallet at " $chain "."]
@@ -403,6 +407,25 @@ macro_rules! declare_chain_options {
 			}
 
 			impl [<$chain SigningParams>] {
+				/// Return transactions mortality.
+				#[allow(dead_code)]
+				pub fn transactions_mortality(&self) -> anyhow::Result<Option<u32>> {
+					self.[<$chain_prefix _transactions_mortality>]
+						.map(|transactions_mortality| {
+							if !(4..=65536).contains(&transactions_mortality)
+								|| !transactions_mortality.is_power_of_two()
+							{
+								Err(anyhow::format_err!(
+									"Transactions mortality {} is not a power of two in a [4; 65536] range",
+									transactions_mortality,
+								))
+							} else {
+								Ok(transactions_mortality)
+							}
+						})
+						.transpose()
+				}
+
 				/// Parse signing params into chain-specific KeyPair.
 				pub fn to_keypair<Chain: CliChain>(&self) -> anyhow::Result<Chain::KeyPair> {
 					let suri = match (self.[<$chain_prefix _signer>].as_ref(), self.[<$chain_prefix _signer_file>].as_ref()) {
@@ -550,6 +573,8 @@ mod tests {
 
 				target_signer_file: None,
 				target_signer_password_file: None,
+
+				target_transactions_mortality: None,
 			}
 			.to_keypair::<relay_rialto_client::Rialto>()
 			.map(|p| p.public())
@@ -565,6 +590,8 @@ mod tests {
 
 				target_signer_file: Some(suri_file_path.clone()),
 				target_signer_password_file: Some(password_file_path.clone()),
+
+				target_transactions_mortality: None,
 			}
 			.to_keypair::<relay_rialto_client::Rialto>()
 			.map(|p| p.public())
@@ -580,6 +607,8 @@ mod tests {
 
 				target_signer_file: Some(suri_file_path.clone()),
 				target_signer_password_file: Some(password_file_path.clone()),
+
+				target_transactions_mortality: None,
 			}
 			.to_keypair::<relay_rialto_client::Rialto>()
 			.map(|p| p.public())
@@ -595,6 +624,8 @@ mod tests {
 
 				target_signer_file: Some(suri_file_path),
 				target_signer_password_file: Some(password_file_path),
+
+				target_transactions_mortality: None,
 			}
 			.to_keypair::<relay_rialto_client::Rialto>()
 			.map(|p| p.public())
diff --git a/bridges/relays/bin-substrate/src/cli/relay_headers.rs b/bridges/relays/bin-substrate/src/cli/relay_headers.rs
index 404e571c2c..0e527eb5b9 100644
--- a/bridges/relays/bin-substrate/src/cli/relay_headers.rs
+++ b/bridges/relays/bin-substrate/src/cli/relay_headers.rs
@@ -99,6 +99,7 @@ impl RelayHeaders {
 		select_bridge!(self.bridge, {
 			let source_client = self.source.to_client::<Source>().await?;
 			let target_client = self.target.to_client::<Target>().await?;
+			let target_transactions_mortality = self.target_sign.target_transactions_mortality;
 			let target_sign = self.target_sign.to_keypair::<Target>()?;
 			let metrics_params = Finality::customize_metrics(self.prometheus_params.into())?;
 			let finality = Finality::new(target_client.clone(), target_sign);
@@ -109,6 +110,7 @@ impl RelayHeaders {
 				source_client,
 				target_client,
 				self.only_mandatory_headers,
+				target_transactions_mortality,
 				metrics_params,
 			)
 			.await
diff --git a/bridges/relays/bin-substrate/src/cli/relay_headers_and_messages.rs b/bridges/relays/bin-substrate/src/cli/relay_headers_and_messages.rs
index a2f0d236a9..236b2b964b 100644
--- a/bridges/relays/bin-substrate/src/cli/relay_headers_and_messages.rs
+++ b/bridges/relays/bin-substrate/src/cli/relay_headers_and_messages.rs
@@ -188,9 +188,11 @@ impl RelayHeadersAndMessages {
 			let params: Params = self.into();
 
 			let left_client = params.left.to_client::<Left>().await?;
+			let left_transactions_mortality = params.left_sign.transactions_mortality()?;
 			let left_sign = params.left_sign.to_keypair::<Left>()?;
 			let left_messages_pallet_owner = params.left_messages_pallet_owner.to_keypair::<Left>()?;
 			let right_client = params.right.to_client::<Right>().await?;
+			let right_transactions_mortality = params.right_sign.transactions_mortality()?;
 			let right_sign = params.right_sign.to_keypair::<Right>()?;
 			let right_messages_pallet_owner = params.right_messages_pallet_owner.to_keypair::<Right>()?;
 
@@ -273,12 +275,14 @@ impl RelayHeadersAndMessages {
 			let left_to_right_on_demand_headers = OnDemandHeadersRelay::new(
 				left_client.clone(),
 				right_client.clone(),
+				right_transactions_mortality,
 				LeftToRightFinality::new(right_client.clone(), right_sign.clone()),
 				MAX_MISSING_LEFT_HEADERS_AT_RIGHT,
 			);
 			let right_to_left_on_demand_headers = OnDemandHeadersRelay::new(
 				right_client.clone(),
 				left_client.clone(),
+				left_transactions_mortality,
 				RightToLeftFinality::new(left_client.clone(), left_sign.clone()),
 				MAX_MISSING_RIGHT_HEADERS_AT_LEFT,
 			);
diff --git a/bridges/relays/bin-substrate/src/cli/send_message.rs b/bridges/relays/bin-substrate/src/cli/send_message.rs
index 6259c85b50..75c3118eb4 100644
--- a/bridges/relays/bin-substrate/src/cli/send_message.rs
+++ b/bridges/relays/bin-substrate/src/cli/send_message.rs
@@ -178,10 +178,11 @@ impl SendMessage {
 
 			let source_genesis_hash = *source_client.genesis_hash();
 			source_client
-				.submit_signed_extrinsic(source_sign.public().into(), move |transaction_nonce| {
+				.submit_signed_extrinsic(source_sign.public().into(), move |_, transaction_nonce| {
 					let signed_source_call = Source::sign_transaction(
 						source_genesis_hash,
 						&source_sign,
+						relay_substrate_client::TransactionEra::immortal(),
 						transaction_nonce,
 						send_message_call,
 					)
diff --git a/bridges/relays/client-millau/src/lib.rs b/bridges/relays/client-millau/src/lib.rs
index ac4368392c..ce1ab87014 100644
--- a/bridges/relays/client-millau/src/lib.rs
+++ b/bridges/relays/client-millau/src/lib.rs
@@ -66,6 +66,7 @@ impl TransactionSignScheme for Millau {
 	fn sign_transaction(
 		genesis_hash: <Self::Chain as ChainBase>::Hash,
 		signer: &Self::AccountKeyPair,
+		era: relay_substrate_client::TransactionEraOf<Self::Chain>,
 		signer_nonce: <Self::Chain as Chain>::Index,
 		call: <Self::Chain as Chain>::Call,
 	) -> Self::SignedTransaction {
@@ -75,7 +76,7 @@ impl TransactionSignScheme for Millau {
 				frame_system::CheckSpecVersion::<millau_runtime::Runtime>::new(),
 				frame_system::CheckTxVersion::<millau_runtime::Runtime>::new(),
 				frame_system::CheckGenesis::<millau_runtime::Runtime>::new(),
-				frame_system::CheckEra::<millau_runtime::Runtime>::from(sp_runtime::generic::Era::Immortal),
+				frame_system::CheckEra::<millau_runtime::Runtime>::from(era.frame_era()),
 				frame_system::CheckNonce::<millau_runtime::Runtime>::from(signer_nonce),
 				frame_system::CheckWeight::<millau_runtime::Runtime>::new(),
 				pallet_transaction_payment::ChargeTransactionPayment::<millau_runtime::Runtime>::from(0),
@@ -84,7 +85,7 @@ impl TransactionSignScheme for Millau {
 				millau_runtime::VERSION.spec_version,
 				millau_runtime::VERSION.transaction_version,
 				genesis_hash,
-				genesis_hash,
+				era.signed_payload(genesis_hash),
 				(),
 				(),
 				(),
diff --git a/bridges/relays/client-rialto/src/lib.rs b/bridges/relays/client-rialto/src/lib.rs
index 646d762923..aaa62eea0e 100644
--- a/bridges/relays/client-rialto/src/lib.rs
+++ b/bridges/relays/client-rialto/src/lib.rs
@@ -66,6 +66,7 @@ impl TransactionSignScheme for Rialto {
 	fn sign_transaction(
 		genesis_hash: <Self::Chain as ChainBase>::Hash,
 		signer: &Self::AccountKeyPair,
+		era: relay_substrate_client::TransactionEraOf<Self::Chain>,
 		signer_nonce: <Self::Chain as Chain>::Index,
 		call: <Self::Chain as Chain>::Call,
 	) -> Self::SignedTransaction {
@@ -75,7 +76,7 @@ impl TransactionSignScheme for Rialto {
 				frame_system::CheckSpecVersion::<rialto_runtime::Runtime>::new(),
 				frame_system::CheckTxVersion::<rialto_runtime::Runtime>::new(),
 				frame_system::CheckGenesis::<rialto_runtime::Runtime>::new(),
-				frame_system::CheckEra::<rialto_runtime::Runtime>::from(sp_runtime::generic::Era::Immortal),
+				frame_system::CheckEra::<rialto_runtime::Runtime>::from(era.frame_era()),
 				frame_system::CheckNonce::<rialto_runtime::Runtime>::from(signer_nonce),
 				frame_system::CheckWeight::<rialto_runtime::Runtime>::new(),
 				pallet_transaction_payment::ChargeTransactionPayment::<rialto_runtime::Runtime>::from(0),
@@ -84,7 +85,7 @@ impl TransactionSignScheme for Rialto {
 				rialto_runtime::VERSION.spec_version,
 				rialto_runtime::VERSION.transaction_version,
 				genesis_hash,
-				genesis_hash,
+				era.signed_payload(genesis_hash),
 				(),
 				(),
 				(),
diff --git a/bridges/relays/client-rococo/src/lib.rs b/bridges/relays/client-rococo/src/lib.rs
index 4d4812e459..25c10999c6 100644
--- a/bridges/relays/client-rococo/src/lib.rs
+++ b/bridges/relays/client-rococo/src/lib.rs
@@ -68,18 +68,13 @@ impl TransactionSignScheme for Rococo {
 	fn sign_transaction(
 		genesis_hash: <Self::Chain as ChainBase>::Hash,
 		signer: &Self::AccountKeyPair,
+		era: relay_substrate_client::TransactionEraOf<Self::Chain>,
 		signer_nonce: <Self::Chain as Chain>::Index,
 		call: <Self::Chain as Chain>::Call,
 	) -> Self::SignedTransaction {
 		let raw_payload = SignedPayload::new(
 			call,
-			bp_rococo::SignedExtensions::new(
-				bp_rococo::VERSION,
-				sp_runtime::generic::Era::Immortal,
-				genesis_hash,
-				signer_nonce,
-				0,
-			),
+			bp_rococo::SignedExtensions::new(bp_rococo::VERSION, era, genesis_hash, signer_nonce, 0),
 		)
 		.expect("SignedExtension never fails.");
 
diff --git a/bridges/relays/client-substrate/src/chain.rs b/bridges/relays/client-substrate/src/chain.rs
index 03cbaef2d8..39d122a72b 100644
--- a/bridges/relays/client-substrate/src/chain.rs
+++ b/bridges/relays/client-substrate/src/chain.rs
@@ -107,6 +107,7 @@ pub trait TransactionSignScheme {
 	fn sign_transaction(
 		genesis_hash: <Self::Chain as ChainBase>::Hash,
 		signer: &Self::AccountKeyPair,
+		era: bp_runtime::TransactionEraOf<Self::Chain>,
 		signer_nonce: <Self::Chain as Chain>::Index,
 		call: <Self::Chain as Chain>::Call,
 	) -> Self::SignedTransaction;
diff --git a/bridges/relays/client-substrate/src/client.rs b/bridges/relays/client-substrate/src/client.rs
index 8164501348..b63e7f30a6 100644
--- a/bridges/relays/client-substrate/src/client.rs
+++ b/bridges/relays/client-substrate/src/client.rs
@@ -18,7 +18,7 @@
 
 use crate::chain::{Chain, ChainWithBalances};
 use crate::rpc::Substrate;
-use crate::{ConnectionParams, Error, Result};
+use crate::{ConnectionParams, Error, HeaderIdOf, Result};
 
 use async_std::sync::{Arc, Mutex};
 use codec::Decode;
@@ -29,8 +29,9 @@ use jsonrpsee_ws_client::{WsClient as RpcClient, WsClientBuilder as RpcClientBui
 use num_traits::{Bounded, Zero};
 use pallet_balances::AccountData;
 use pallet_transaction_payment::InclusionFee;
-use relay_utils::relay_loop::RECONNECT_DELAY;
+use relay_utils::{relay_loop::RECONNECT_DELAY, HeaderId};
 use sp_core::{storage::StorageKey, Bytes};
+use sp_runtime::traits::Header as HeaderT;
 use sp_trie::StorageProof;
 use sp_version::RuntimeVersion;
 use std::{convert::TryFrom, future::Future};
@@ -293,12 +294,14 @@ impl<C: Chain> Client<C> {
 	pub async fn submit_signed_extrinsic(
 		&self,
 		extrinsic_signer: C::AccountId,
-		prepare_extrinsic: impl FnOnce(C::Index) -> Bytes + Send + 'static,
+		prepare_extrinsic: impl FnOnce(HeaderIdOf<C>, C::Index) -> Bytes + Send + 'static,
 	) -> Result<C::Hash> {
 		let _guard = self.submit_signed_extrinsic_lock.lock().await;
 		let transaction_nonce = self.next_account_index(extrinsic_signer).await?;
+		let best_header = self.best_header().await?;
+		let best_header_id = HeaderId(*best_header.number(), best_header.hash());
 		self.jsonrpsee_execute(move |client| async move {
-			let extrinsic = prepare_extrinsic(transaction_nonce);
+			let extrinsic = prepare_extrinsic(best_header_id, transaction_nonce);
 			let tx_hash = Substrate::<C>::author_submit_extrinsic(&*client, extrinsic).await?;
 			log::trace!(target: "bridge", "Sent transaction to {} node: {:?}", C::NAME, tx_hash);
 			Ok(tx_hash)
diff --git a/bridges/relays/client-substrate/src/lib.rs b/bridges/relays/client-substrate/src/lib.rs
index 44895dcdc6..2648fc4ff2 100644
--- a/bridges/relays/client-substrate/src/lib.rs
+++ b/bridges/relays/client-substrate/src/lib.rs
@@ -29,11 +29,13 @@ pub mod guard;
 pub mod headers_source;
 pub mod metrics;
 
+use std::time::Duration;
+
 pub use crate::chain::{BlockWithJustification, Chain, ChainWithBalances, TransactionSignScheme};
 pub use crate::client::{Client, JustificationsSubscription, OpaqueGrandpaAuthoritiesSet};
 pub use crate::error::{Error, Result};
 pub use crate::sync_header::SyncHeader;
-pub use bp_runtime::{BlockNumberOf, Chain as ChainBase, HashOf, HeaderOf};
+pub use bp_runtime::{BlockNumberOf, Chain as ChainBase, HashOf, HeaderOf, TransactionEra, TransactionEraOf};
 
 /// Header id used by the chain.
 pub type HeaderIdOf<C> = relay_utils::HeaderId<HashOf<C>, BlockNumberOf<C>>;
@@ -58,3 +60,14 @@ impl Default for ConnectionParams {
 		}
 	}
 }
+
+/// Returns stall timeout for relay loop.
+///
+/// Relay considers himself stalled if he has submitted transaction to the node, but it has not
+/// been mined for this period.
+///
+/// Returns `None` if mortality period is `None`
+pub fn transaction_stall_timeout(mortality_period: Option<u32>, average_block_interval: Duration) -> Option<Duration> {
+	// 1 extra block for transaction to reach the pool && 1 for relayer to awake after it is mined
+	mortality_period.map(|mortality_period| average_block_interval.saturating_mul(mortality_period + 1 + 1))
+}
diff --git a/bridges/relays/client-westend/src/lib.rs b/bridges/relays/client-westend/src/lib.rs
index b2347da502..fefab00c56 100644
--- a/bridges/relays/client-westend/src/lib.rs
+++ b/bridges/relays/client-westend/src/lib.rs
@@ -66,18 +66,13 @@ impl TransactionSignScheme for Westend {
 	fn sign_transaction(
 		genesis_hash: <Self::Chain as ChainBase>::Hash,
 		signer: &Self::AccountKeyPair,
+		era: relay_substrate_client::TransactionEraOf<Self::Chain>,
 		signer_nonce: <Self::Chain as Chain>::Index,
 		call: <Self::Chain as Chain>::Call,
 	) -> Self::SignedTransaction {
 		let raw_payload = SignedPayload::new(
 			call,
-			bp_westend::SignedExtensions::new(
-				bp_westend::VERSION,
-				sp_runtime::generic::Era::Immortal,
-				genesis_hash,
-				signer_nonce,
-				0,
-			),
+			bp_westend::SignedExtensions::new(bp_westend::VERSION, era, genesis_hash, signer_nonce, 0),
 		)
 		.expect("SignedExtension never fails.");
 
diff --git a/bridges/relays/client-wococo/src/lib.rs b/bridges/relays/client-wococo/src/lib.rs
index 3ef55223b5..4b3bdd7d84 100644
--- a/bridges/relays/client-wococo/src/lib.rs
+++ b/bridges/relays/client-wococo/src/lib.rs
@@ -68,18 +68,13 @@ impl TransactionSignScheme for Wococo {
 	fn sign_transaction(
 		genesis_hash: <Self::Chain as ChainBase>::Hash,
 		signer: &Self::AccountKeyPair,
+		era: bp_runtime::TransactionEraOf<Self::Chain>,
 		signer_nonce: <Self::Chain as Chain>::Index,
 		call: <Self::Chain as Chain>::Call,
 	) -> Self::SignedTransaction {
 		let raw_payload = SignedPayload::new(
 			call,
-			bp_wococo::SignedExtensions::new(
-				bp_wococo::VERSION,
-				sp_runtime::generic::Era::Immortal,
-				genesis_hash,
-				signer_nonce,
-				0,
-			),
+			bp_wococo::SignedExtensions::new(bp_wococo::VERSION, era, genesis_hash, signer_nonce, 0),
 		)
 		.expect("SignedExtension never fails.");
 
diff --git a/bridges/relays/lib-substrate-relay/src/finality_pipeline.rs b/bridges/relays/lib-substrate-relay/src/finality_pipeline.rs
index 2dc9a63947..73a346f217 100644
--- a/bridges/relays/lib-substrate-relay/src/finality_pipeline.rs
+++ b/bridges/relays/lib-substrate-relay/src/finality_pipeline.rs
@@ -25,8 +25,14 @@ use relay_utils::{metrics::MetricsParams, BlockNumberBase};
 use sp_core::Bytes;
 use std::{fmt::Debug, marker::PhantomData, time::Duration};
 
-/// Default synchronization loop timeout.
-pub(crate) const STALL_TIMEOUT: Duration = Duration::from_secs(120);
+/// Default synchronization loop timeout. If transactions generated by relay are immortal, then
+/// this timeout is used.
+///
+/// There are no any strict requirements on block time in Substrate. But we assume here that all
+/// Substrate-based chains will be designed to produce relatively fast (compared to slowest
+/// blockchains) blocks. So 1 hour seems to be a good guess for (even congested) chains to mine
+/// transaction, or remove it from the pool.
+pub(crate) const STALL_TIMEOUT: Duration = Duration::from_secs(60 * 60);
 /// Default limit of recent finality proofs.
 ///
 /// Finality delay of 4096 blocks is unlikely to happen in practice in
@@ -62,6 +68,7 @@ pub trait SubstrateFinalitySyncPipeline: 'static + Clone + Debug + Send + Sync {
 	/// Make submit header transaction.
 	fn make_submit_finality_proof_transaction(
 		&self,
+		era: bp_runtime::TransactionEraOf<Self::TargetChain>,
 		transaction_nonce: <Self::TargetChain as Chain>::Index,
 		header: <Self::FinalitySyncPipeline as FinalitySyncPipeline>::Header,
 		proof: <Self::FinalitySyncPipeline as FinalitySyncPipeline>::FinalityProof,
@@ -123,6 +130,7 @@ pub async fn run<SourceChain, TargetChain, P>(
 	source_client: Client<SourceChain>,
 	target_client: Client<TargetChain>,
 	only_mandatory_headers: bool,
+	transactions_mortality: Option<u32>,
 	metrics_params: MetricsParams,
 ) -> anyhow::Result<()>
 where
@@ -146,11 +154,15 @@ where
 
 	finality_relay::run(
 		FinalitySource::new(source_client, None),
-		SubstrateFinalityTarget::new(target_client, pipeline),
+		SubstrateFinalityTarget::new(target_client, pipeline, transactions_mortality),
 		FinalitySyncParams {
 			tick: std::cmp::max(SourceChain::AVERAGE_BLOCK_INTERVAL, TargetChain::AVERAGE_BLOCK_INTERVAL),
 			recent_finality_proofs_limit: RECENT_FINALITY_PROOFS_LIMIT,
-			stall_timeout: STALL_TIMEOUT,
+			stall_timeout: relay_substrate_client::transaction_stall_timeout(
+				transactions_mortality,
+				TargetChain::AVERAGE_BLOCK_INTERVAL,
+			)
+			.unwrap_or(STALL_TIMEOUT),
 			only_mandatory_headers,
 		},
 		metrics_params,
diff --git a/bridges/relays/lib-substrate-relay/src/finality_target.rs b/bridges/relays/lib-substrate-relay/src/finality_target.rs
index bcf09b1a6d..5db7d080ab 100644
--- a/bridges/relays/lib-substrate-relay/src/finality_target.rs
+++ b/bridges/relays/lib-substrate-relay/src/finality_target.rs
@@ -30,12 +30,17 @@ use relay_utils::relay_loop::Client as RelayClient;
 pub struct SubstrateFinalityTarget<C: Chain, P> {
 	client: Client<C>,
 	pipeline: P,
+	transactions_mortality: Option<u32>,
 }
 
 impl<C: Chain, P> SubstrateFinalityTarget<C, P> {
 	/// Create new Substrate headers target.
-	pub fn new(client: Client<C>, pipeline: P) -> Self {
-		SubstrateFinalityTarget { client, pipeline }
+	pub fn new(client: Client<C>, pipeline: P, transactions_mortality: Option<u32>) -> Self {
+		SubstrateFinalityTarget {
+			client,
+			pipeline,
+			transactions_mortality,
+		}
 	}
 }
 
@@ -44,6 +49,7 @@ impl<C: Chain, P: SubstrateFinalitySyncPipeline> Clone for SubstrateFinalityTarg
 		SubstrateFinalityTarget {
 			client: self.client.clone(),
 			pipeline: self.pipeline.clone(),
+			transactions_mortality: self.transactions_mortality,
 		}
 	}
 }
@@ -89,9 +95,19 @@ where
 	) -> Result<(), SubstrateError> {
 		let transactions_author = self.pipeline.transactions_author();
 		let pipeline = self.pipeline.clone();
+		let transactions_mortality = self.transactions_mortality;
 		self.client
-			.submit_signed_extrinsic(transactions_author, move |transaction_nonce| {
-				pipeline.make_submit_finality_proof_transaction(transaction_nonce, header, proof)
+			.submit_signed_extrinsic(transactions_author, move |best_block_id, transaction_nonce| {
+				pipeline.make_submit_finality_proof_transaction(
+					relay_substrate_client::TransactionEra::new(
+						best_block_id.0,
+						best_block_id.1,
+						transactions_mortality,
+					),
+					transaction_nonce,
+					header,
+					proof,
+				)
 			})
 			.await
 			.map(drop)
diff --git a/bridges/relays/lib-substrate-relay/src/headers_initialize.rs b/bridges/relays/lib-substrate-relay/src/headers_initialize.rs
index d3a78028e0..4a7a0798bb 100644
--- a/bridges/relays/lib-substrate-relay/src/headers_initialize.rs
+++ b/bridges/relays/lib-substrate-relay/src/headers_initialize.rs
@@ -88,7 +88,7 @@ async fn do_initialize<SourceChain: Chain, TargetChain: Chain>(
 	);
 
 	let initialization_tx_hash = target_client
-		.submit_signed_extrinsic(target_transactions_signer, move |transaction_nonce| {
+		.submit_signed_extrinsic(target_transactions_signer, move |_, transaction_nonce| {
 			prepare_initialize_transaction(transaction_nonce, initialization_data)
 		})
 		.await
diff --git a/bridges/relays/lib-substrate-relay/src/messages_source.rs b/bridges/relays/lib-substrate-relay/src/messages_source.rs
index a442ebfb44..3924c6d3a5 100644
--- a/bridges/relays/lib-substrate-relay/src/messages_source.rs
+++ b/bridges/relays/lib-substrate-relay/src/messages_source.rs
@@ -246,7 +246,7 @@ where
 	) -> Result<(), SubstrateError> {
 		let lane = self.lane.clone();
 		self.client
-			.submit_signed_extrinsic(self.lane.source_transactions_author(), move |transaction_nonce| {
+			.submit_signed_extrinsic(self.lane.source_transactions_author(), move |_, transaction_nonce| {
 				lane.make_messages_receiving_proof_transaction(transaction_nonce, generated_at_block, proof)
 			})
 			.await?;
diff --git a/bridges/relays/lib-substrate-relay/src/messages_target.rs b/bridges/relays/lib-substrate-relay/src/messages_target.rs
index 1db8345931..3b8e749a60 100644
--- a/bridges/relays/lib-substrate-relay/src/messages_target.rs
+++ b/bridges/relays/lib-substrate-relay/src/messages_target.rs
@@ -229,7 +229,7 @@ where
 		let lane = self.lane.clone();
 		let nonces_clone = nonces.clone();
 		self.client
-			.submit_signed_extrinsic(self.lane.target_transactions_author(), move |transaction_nonce| {
+			.submit_signed_extrinsic(self.lane.target_transactions_author(), move |_, transaction_nonce| {
 				lane.make_messages_delivery_transaction(transaction_nonce, generated_at_header, nonces_clone, proof)
 			})
 			.await?;
diff --git a/bridges/relays/lib-substrate-relay/src/on_demand_headers.rs b/bridges/relays/lib-substrate-relay/src/on_demand_headers.rs
index 74166b89e7..2f8441dbfc 100644
--- a/bridges/relays/lib-substrate-relay/src/on_demand_headers.rs
+++ b/bridges/relays/lib-substrate-relay/src/on_demand_headers.rs
@@ -56,6 +56,7 @@ impl<SourceChain: Chain> OnDemandHeadersRelay<SourceChain> {
 	pub fn new<TargetChain: Chain, TargetSign, P>(
 		source_client: Client<SourceChain>,
 		target_client: Client<TargetChain>,
+		target_transactions_mortality: Option<u32>,
 		pipeline: P,
 		maximal_headers_difference: SourceChain::BlockNumber,
 	) -> Self
@@ -79,6 +80,7 @@ impl<SourceChain: Chain> OnDemandHeadersRelay<SourceChain> {
 			background_task(
 				source_client,
 				target_client,
+				target_transactions_mortality,
 				pipeline,
 				maximal_headers_difference,
 				required_header_number,
@@ -110,7 +112,7 @@ impl<SourceChain: Chain> OnDemandHeadersRelay<SourceChain> {
 async fn background_task<SourceChain, TargetChain, TargetSign, P>(
 	source_client: Client<SourceChain>,
 	target_client: Client<TargetChain>,
-	// pipeline: SubstrateFinalityToSubstrate<SourceChain, TargetChain, TargetSign>,
+	target_transactions_mortality: Option<u32>,
 	pipeline: P,
 	maximal_headers_difference: SourceChain::BlockNumber,
 	required_header_number: RequiredHeaderNumberRef<SourceChain>,
@@ -130,7 +132,8 @@ async fn background_task<SourceChain, TargetChain, TargetSign, P>(
 		_,
 		SubstrateFinalityToSubstrate<SourceChain, TargetChain, TargetSign>,
 	>::new(source_client.clone(), Some(required_header_number.clone()));
-	let mut finality_target = SubstrateFinalityTarget::new(target_client.clone(), pipeline.clone());
+	let mut finality_target =
+		SubstrateFinalityTarget::new(target_client.clone(), pipeline.clone(), target_transactions_mortality);
 	let mut latest_non_mandatory_at_source = Zero::zero();
 
 	let mut restart_relay = true;