diff --git a/polkadot/node/client/src/lib.rs b/polkadot/node/client/src/lib.rs
index c358523ef1..cbf84d609a 100644
--- a/polkadot/node/client/src/lib.rs
+++ b/polkadot/node/client/src/lib.rs
@@ -19,8 +19,9 @@
 //! Provides the [`AbstractClient`] trait that is a super trait that combines all the traits the client implements.
 //! There is also the [`Client`] enum that combines all the different clients into one common structure.
 
-use polkadot_primitives::v1::{
-	AccountId, Balance, Block, BlockNumber, Hash, Header, Nonce, ParachainHost,
+use polkadot_primitives::{
+	v1::{AccountId, Balance, Block, BlockNumber, Hash, Header, Nonce},
+	v2::ParachainHost,
 };
 use sc_client_api::{AuxStore, Backend as BackendT, BlockchainEvents, KeyIterator, UsageProvider};
 use sc_executor::NativeElseWasmExecutor;
diff --git a/polkadot/node/core/approval-voting/src/criteria.rs b/polkadot/node/core/approval-voting/src/criteria.rs
index e96cf06451..dc4ce82152 100644
--- a/polkadot/node/core/approval-voting/src/criteria.rs
+++ b/polkadot/node/core/approval-voting/src/criteria.rs
@@ -20,8 +20,9 @@ use parity_scale_codec::{Decode, Encode};
 use polkadot_node_primitives::approval::{
 	self as approval_types, AssignmentCert, AssignmentCertKind, DelayTranche, RelayVRFStory,
 };
-use polkadot_primitives::v1::{
-	AssignmentId, AssignmentPair, CandidateHash, CoreIndex, GroupIndex, SessionInfo, ValidatorIndex,
+use polkadot_primitives::{
+	v1::{AssignmentId, AssignmentPair, CandidateHash, CoreIndex, GroupIndex, ValidatorIndex},
+	v2::SessionInfo,
 };
 use sc_keystore::LocalKeystore;
 use sp_application_crypto::ByteArray;
diff --git a/polkadot/node/core/approval-voting/src/import.rs b/polkadot/node/core/approval-voting/src/import.rs
index 7937013882..32d7fe7118 100644
--- a/polkadot/node/core/approval-voting/src/import.rs
+++ b/polkadot/node/core/approval-voting/src/import.rs
@@ -582,7 +582,7 @@ pub(crate) mod tests {
 	use polkadot_node_primitives::approval::{VRFOutput, VRFProof};
 	use polkadot_node_subsystem::messages::AllMessages;
 	use polkadot_node_subsystem_test_helpers::make_subsystem_context;
-	use polkadot_primitives::v1::{SessionInfo, ValidatorIndex};
+	use polkadot_primitives::{v1::ValidatorIndex, v2::SessionInfo};
 	pub(crate) use sp_consensus_babe::{
 		digests::{CompatibleDigestItem, PreDigest, SecondaryVRFPreDigest},
 		AllowedSlots, BabeEpochConfiguration, Epoch as BabeEpoch,
@@ -685,6 +685,7 @@ pub(crate) mod tests {
 			n_delay_tranches: index as _,
 			no_show_slots: index as _,
 			needed_approvals: index as _,
+			active_validator_indices: Vec::new(),
 		}
 	}
 
@@ -1140,6 +1141,7 @@ pub(crate) mod tests {
 			relay_vrf_modulo_samples: irrelevant,
 			n_delay_tranches: irrelevant,
 			no_show_slots: irrelevant,
+			active_validator_indices: Vec::new(),
 		};
 
 		let slot = Slot::from(10);
diff --git a/polkadot/node/core/approval-voting/src/lib.rs b/polkadot/node/core/approval-voting/src/lib.rs
index c4778fe6f6..9664d97a75 100644
--- a/polkadot/node/core/approval-voting/src/lib.rs
+++ b/polkadot/node/core/approval-voting/src/lib.rs
@@ -50,10 +50,13 @@ use polkadot_node_subsystem_util::{
 	},
 	TimeoutExt,
 };
-use polkadot_primitives::v1::{
-	ApprovalVote, BlockNumber, CandidateHash, CandidateIndex, CandidateReceipt, DisputeStatement,
-	GroupIndex, Hash, SessionIndex, SessionInfo, ValidDisputeStatementKind, ValidatorId,
-	ValidatorIndex, ValidatorPair, ValidatorSignature,
+use polkadot_primitives::{
+	v1::{
+		ApprovalVote, BlockNumber, CandidateHash, CandidateIndex, CandidateReceipt,
+		DisputeStatement, GroupIndex, Hash, SessionIndex, ValidDisputeStatementKind, ValidatorId,
+		ValidatorIndex, ValidatorPair, ValidatorSignature,
+	},
+	v2::SessionInfo,
 };
 use sc_keystore::LocalKeystore;
 use sp_application_crypto::Pair;
diff --git a/polkadot/node/core/approval-voting/src/tests.rs b/polkadot/node/core/approval-voting/src/tests.rs
index 8e69cb88aa..10eaeafc3d 100644
--- a/polkadot/node/core/approval-voting/src/tests.rs
+++ b/polkadot/node/core/approval-voting/src/tests.rs
@@ -740,6 +740,22 @@ impl ChainBuilder {
 	}
 }
 
+fn session_info(keys: &[Sr25519Keyring]) -> SessionInfo {
+	SessionInfo {
+		validators: keys.iter().map(|v| v.public().into()).collect(),
+		discovery_keys: keys.iter().map(|v| v.public().into()).collect(),
+		assignment_keys: keys.iter().map(|v| v.public().into()).collect(),
+		validator_groups: vec![vec![ValidatorIndex(0)], vec![ValidatorIndex(1)]],
+		n_cores: keys.len() as _,
+		needed_approvals: 2,
+		zeroth_delay_tranche_width: 5,
+		relay_vrf_modulo_samples: 3,
+		n_delay_tranches: 50,
+		no_show_slots: 2,
+		active_validator_indices: vec![],
+	}
+}
+
 async fn import_block(
 	overseer: &mut VirtualOverseer,
 	hashes: &[(Hash, Header)],
@@ -757,18 +773,7 @@ async fn import_block(
 
 	let session_info = config.session_info.clone().unwrap_or({
 		let validators = vec![Sr25519Keyring::Alice, Sr25519Keyring::Bob];
-		SessionInfo {
-			validators: validators.iter().map(|v| v.public().into()).collect(),
-			discovery_keys: validators.iter().map(|v| v.public().into()).collect(),
-			assignment_keys: validators.iter().map(|v| v.public().into()).collect(),
-			validator_groups: vec![vec![ValidatorIndex(0)], vec![ValidatorIndex(1)]],
-			n_cores: validators.len() as _,
-			needed_approvals: 1,
-			zeroth_delay_tranche_width: 5,
-			relay_vrf_modulo_samples: 3,
-			n_delay_tranches: 50,
-			no_show_slots: 2,
-		}
+		SessionInfo { needed_approvals: 1, ..session_info(&validators) }
 	});
 
 	overseer_send(
@@ -1452,20 +1457,13 @@ fn subsystem_second_approval_import_only_schedules_wakeups() {
 			Sr25519Keyring::Eve,
 		];
 		let session_info = SessionInfo {
-			validators: validators.iter().map(|v| v.public().into()).collect(),
 			validator_groups: vec![
 				vec![ValidatorIndex(0), ValidatorIndex(1)],
 				vec![ValidatorIndex(2)],
 				vec![ValidatorIndex(3), ValidatorIndex(4)],
 			],
 			needed_approvals: 1,
-			discovery_keys: validators.iter().map(|v| v.public().into()).collect(),
-			assignment_keys: validators.iter().map(|v| v.public().into()).collect(),
-			n_cores: validators.len() as _,
-			zeroth_delay_tranche_width: 5,
-			relay_vrf_modulo_samples: 3,
-			n_delay_tranches: 50,
-			no_show_slots: 2,
+			..session_info(&validators)
 		};
 
 		// Add block hash 0x01...
@@ -1763,20 +1761,12 @@ fn import_checked_approval_updates_entries_and_schedules() {
 			Sr25519Keyring::Eve,
 		];
 		let session_info = SessionInfo {
-			validators: validators.iter().map(|v| v.public().into()).collect(),
 			validator_groups: vec![
 				vec![ValidatorIndex(0), ValidatorIndex(1)],
 				vec![ValidatorIndex(2)],
 				vec![ValidatorIndex(3), ValidatorIndex(4)],
 			],
-			needed_approvals: 2,
-			discovery_keys: validators.iter().map(|v| v.public().into()).collect(),
-			assignment_keys: validators.iter().map(|v| v.public().into()).collect(),
-			n_cores: validators.len() as _,
-			zeroth_delay_tranche_width: 5,
-			relay_vrf_modulo_samples: 3,
-			n_delay_tranches: 50,
-			no_show_slots: 2,
+			..session_info(&validators)
 		};
 
 		let candidate_descriptor = make_candidate(1.into(), &block_hash);
@@ -1923,20 +1913,12 @@ fn subsystem_import_checked_approval_sets_one_block_bit_at_a_time() {
 			Sr25519Keyring::Eve,
 		];
 		let session_info = SessionInfo {
-			validators: validators.iter().map(|v| v.public().into()).collect(),
 			validator_groups: vec![
 				vec![ValidatorIndex(0), ValidatorIndex(1)],
 				vec![ValidatorIndex(2)],
 				vec![ValidatorIndex(3), ValidatorIndex(4)],
 			],
-			needed_approvals: 2,
-			discovery_keys: validators.iter().map(|v| v.public().into()).collect(),
-			assignment_keys: validators.iter().map(|v| v.public().into()).collect(),
-			n_cores: validators.len() as _,
-			zeroth_delay_tranche_width: 5,
-			relay_vrf_modulo_samples: 3,
-			n_delay_tranches: 50,
-			no_show_slots: 2,
+			..session_info(&validators)
 		};
 
 		ChainBuilder::new()
@@ -2209,20 +2191,12 @@ fn subsystem_validate_approvals_cache() {
 			Sr25519Keyring::Eve,
 		];
 		let session_info = SessionInfo {
-			validators: validators.iter().map(|v| v.public().into()).collect(),
 			validator_groups: vec![
 				vec![ValidatorIndex(0), ValidatorIndex(1)],
 				vec![ValidatorIndex(2)],
 				vec![ValidatorIndex(3), ValidatorIndex(4)],
 			],
-			needed_approvals: 2,
-			discovery_keys: validators.iter().map(|v| v.public().into()).collect(),
-			assignment_keys: validators.iter().map(|v| v.public().into()).collect(),
-			n_cores: validators.len() as _,
-			zeroth_delay_tranche_width: 5,
-			relay_vrf_modulo_samples: 3,
-			n_delay_tranches: 50,
-			no_show_slots: 2,
+			..session_info(&validators)
 		};
 
 		let candidates = Some(vec![(candidate_receipt.clone(), CoreIndex(0), GroupIndex(0))]);
@@ -2422,20 +2396,14 @@ where
 			Sr25519Keyring::Ferdie,
 		];
 		let session_info = SessionInfo {
-			validators: validators.iter().map(|v| v.public().into()).collect(),
 			validator_groups: vec![
 				vec![ValidatorIndex(0), ValidatorIndex(1)],
 				vec![ValidatorIndex(2), ValidatorIndex(3)],
 				vec![ValidatorIndex(4), ValidatorIndex(5)],
 			],
-			needed_approvals: 2,
-			discovery_keys: validators.iter().map(|v| v.public().into()).collect(),
-			assignment_keys: validators.iter().map(|v| v.public().into()).collect(),
-			n_cores: validators.len() as _,
-			zeroth_delay_tranche_width: 5,
 			relay_vrf_modulo_samples: 2,
-			n_delay_tranches: 50,
 			no_show_slots,
+			..session_info(&validators)
 		};
 
 		ChainBuilder::new()
@@ -2740,20 +2708,12 @@ fn pre_covers_dont_stall_approval() {
 			Sr25519Keyring::One,
 		];
 		let session_info = SessionInfo {
-			validators: validators.iter().map(|v| v.public().into()).collect(),
 			validator_groups: vec![
 				vec![ValidatorIndex(0), ValidatorIndex(1)],
 				vec![ValidatorIndex(2), ValidatorIndex(5)],
 				vec![ValidatorIndex(3), ValidatorIndex(4)],
 			],
-			needed_approvals: 2,
-			discovery_keys: validators.iter().map(|v| v.public().into()).collect(),
-			assignment_keys: validators.iter().map(|v| v.public().into()).collect(),
-			n_cores: validators.len() as _,
-			zeroth_delay_tranche_width: 5,
-			relay_vrf_modulo_samples: 3,
-			n_delay_tranches: 50,
-			no_show_slots: 2,
+			..session_info(&validators)
 		};
 
 		let candidate_descriptor = make_candidate(1.into(), &block_hash);
@@ -2920,20 +2880,12 @@ fn waits_until_approving_assignments_are_old_enough() {
 			Sr25519Keyring::One,
 		];
 		let session_info = SessionInfo {
-			validators: validators.iter().map(|v| v.public().into()).collect(),
 			validator_groups: vec![
 				vec![ValidatorIndex(0), ValidatorIndex(1)],
 				vec![ValidatorIndex(2), ValidatorIndex(5)],
 				vec![ValidatorIndex(3), ValidatorIndex(4)],
 			],
-			needed_approvals: 2,
-			discovery_keys: validators.iter().map(|v| v.public().into()).collect(),
-			assignment_keys: validators.iter().map(|v| v.public().into()).collect(),
-			n_cores: validators.len() as _,
-			zeroth_delay_tranche_width: 5,
-			relay_vrf_modulo_samples: 3,
-			n_delay_tranches: 50,
-			no_show_slots: 2,
+			..session_info(&validators)
 		};
 
 		let candidate_descriptor = make_candidate(1.into(), &block_hash);
diff --git a/polkadot/node/core/dispute-coordinator/src/real/initialized.rs b/polkadot/node/core/dispute-coordinator/src/real/initialized.rs
index 67e1400120..5b9f6d9f06 100644
--- a/polkadot/node/core/dispute-coordinator/src/real/initialized.rs
+++ b/polkadot/node/core/dispute-coordinator/src/real/initialized.rs
@@ -39,10 +39,13 @@ use polkadot_node_subsystem::{
 use polkadot_node_subsystem_util::rolling_session_window::{
 	RollingSessionWindow, SessionWindowUpdate,
 };
-use polkadot_primitives::v1::{
-	byzantine_threshold, BlockNumber, CandidateHash, CandidateReceipt, CompactStatement,
-	DisputeStatement, DisputeStatementSet, Hash, ScrapedOnChainVotes, SessionIndex, SessionInfo,
-	ValidDisputeStatementKind, ValidatorId, ValidatorIndex, ValidatorPair, ValidatorSignature,
+use polkadot_primitives::{
+	v1::{
+		byzantine_threshold, BlockNumber, CandidateHash, CandidateReceipt, CompactStatement,
+		DisputeStatement, DisputeStatementSet, Hash, ScrapedOnChainVotes, SessionIndex,
+		ValidDisputeStatementKind, ValidatorId, ValidatorIndex, ValidatorPair, ValidatorSignature,
+	},
+	v2::SessionInfo,
 };
 
 use crate::{metrics::Metrics, real::DisputeCoordinatorSubsystem, LOG_TARGET};
diff --git a/polkadot/node/core/dispute-coordinator/src/real/tests.rs b/polkadot/node/core/dispute-coordinator/src/real/tests.rs
index cf264572e2..a2c91998fe 100644
--- a/polkadot/node/core/dispute-coordinator/src/real/tests.rs
+++ b/polkadot/node/core/dispute-coordinator/src/real/tests.rs
@@ -54,10 +54,13 @@ use polkadot_node_subsystem::{
 	ActivatedLeaf, ActiveLeavesUpdate, LeafStatus,
 };
 use polkadot_node_subsystem_test_helpers::{make_subsystem_context, TestSubsystemContextHandle};
-use polkadot_primitives::v1::{
-	BlakeTwo256, BlockNumber, CandidateCommitments, CandidateHash, CandidateReceipt, Hash, HashT,
-	Header, MultiDisputeStatementSet, ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidatorId,
-	ValidatorIndex,
+use polkadot_primitives::{
+	v1::{
+		BlakeTwo256, BlockNumber, CandidateCommitments, CandidateHash, CandidateReceipt, Hash,
+		HashT, Header, MultiDisputeStatementSet, ScrapedOnChainVotes, SessionIndex, ValidatorId,
+		ValidatorIndex,
+	},
+	v2::SessionInfo,
 };
 
 use crate::{
@@ -313,6 +316,7 @@ impl TestState {
 			n_delay_tranches: 100,
 			no_show_slots: 1,
 			needed_approvals: 10,
+			active_validator_indices: Vec::new(),
 		}
 	}
 
diff --git a/polkadot/node/core/runtime-api/src/cache.rs b/polkadot/node/core/runtime-api/src/cache.rs
index 0236466116..1ba246fa15 100644
--- a/polkadot/node/core/runtime-api/src/cache.rs
+++ b/polkadot/node/core/runtime-api/src/cache.rs
@@ -20,12 +20,15 @@ use memory_lru::{MemoryLruCache, ResidentSize};
 use parity_util_mem::{MallocSizeOf, MallocSizeOfExt};
 use sp_consensus_babe::Epoch;
 
-use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, BlockNumber, CandidateCommitments, CandidateEvent,
-	CommittedCandidateReceipt, CoreState, GroupRotationInfo, Hash, Id as ParaId,
-	InboundDownwardMessage, InboundHrmpMessage, OccupiedCoreAssumption, PersistedValidationData,
-	PvfCheckStatement, ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidationCode,
-	ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature,
+use polkadot_primitives::{
+	v1::{
+		AuthorityDiscoveryId, BlockNumber, CandidateCommitments, CandidateEvent,
+		CommittedCandidateReceipt, CoreState, GroupRotationInfo, Hash, Id as ParaId,
+		InboundDownwardMessage, InboundHrmpMessage, OccupiedCoreAssumption,
+		PersistedValidationData, ScrapedOnChainVotes, SessionIndex, ValidationCode,
+		ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature,
+	},
+	v2::{PvfCheckStatement, SessionInfo},
 };
 
 const AUTHORITIES_CACHE_SIZE: usize = 128 * 1024;
diff --git a/polkadot/node/core/runtime-api/src/lib.rs b/polkadot/node/core/runtime-api/src/lib.rs
index 0bca3d5ab3..019705c530 100644
--- a/polkadot/node/core/runtime-api/src/lib.rs
+++ b/polkadot/node/core/runtime-api/src/lib.rs
@@ -23,7 +23,10 @@
 #![warn(missing_docs)]
 
 use polkadot_node_subsystem_util::metrics::{self, prometheus};
-use polkadot_primitives::v1::{Block, BlockId, Hash, ParachainHost};
+use polkadot_primitives::{
+	v1::{Block, BlockId, Hash},
+	v2::ParachainHost,
+};
 use polkadot_subsystem::{
 	errors::RuntimeApiError,
 	messages::{RuntimeApiMessage, RuntimeApiRequest as Request},
@@ -429,8 +432,42 @@ where
 		),
 		Request::CandidateEvents(sender) =>
 			query!(CandidateEvents, candidate_events(), ver = 1, sender),
-		Request::SessionInfo(index, sender) =>
-			query!(SessionInfo, session_info(index), ver = 1, sender),
+		Request::SessionInfo(index, sender) => {
+			use sp_api::ApiExt;
+
+			let api = client.runtime_api();
+			let block_id = BlockId::Hash(relay_parent);
+
+			let api_version = api
+				.api_version::<dyn ParachainHost<Block>>(&BlockId::Hash(relay_parent))
+				.unwrap_or_default()
+				.unwrap_or_default();
+
+			let res = if api_version >= 2 {
+				let res =
+					api.session_info(&block_id, index).map_err(|e| RuntimeApiError::Execution {
+						runtime_api_name: "SessionInfo",
+						source: std::sync::Arc::new(e),
+					});
+				metrics.on_request(res.is_ok());
+				res
+			} else {
+				#[allow(deprecated)]
+				let res = api.session_info_before_version_2(&block_id, index).map_err(|e| {
+					RuntimeApiError::Execution {
+						runtime_api_name: "SessionInfo",
+						source: std::sync::Arc::new(e),
+					}
+				});
+				metrics.on_request(res.is_ok());
+
+				res.map(|r| r.map(|old| old.into()))
+			};
+
+			let _ = sender.send(res.clone());
+
+			res.ok().map(|res| RequestResult::SessionInfo(relay_parent, index, res))
+		},
 		Request::DmqContents(id, sender) => query!(DmqContents, dmq_contents(id), ver = 1, sender),
 		Request::InboundHrmpChannelsContents(id, sender) =>
 			query!(InboundHrmpChannelsContents, inbound_hrmp_channels_contents(id), ver = 1, sender),
diff --git a/polkadot/node/core/runtime-api/src/tests.rs b/polkadot/node/core/runtime-api/src/tests.rs
index 8f50d8bd27..2758d5d36d 100644
--- a/polkadot/node/core/runtime-api/src/tests.rs
+++ b/polkadot/node/core/runtime-api/src/tests.rs
@@ -20,11 +20,14 @@ use ::test_helpers::{dummy_committed_candidate_receipt, dummy_validation_code};
 use futures::channel::oneshot;
 use polkadot_node_primitives::{BabeAllowedSlots, BabeEpoch, BabeEpochConfiguration};
 use polkadot_node_subsystem_test_helpers::make_subsystem_context;
-use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, CandidateEvent, CommittedCandidateReceipt, CoreState, GroupRotationInfo,
-	Id as ParaId, InboundDownwardMessage, InboundHrmpMessage, OccupiedCoreAssumption,
-	PersistedValidationData, PvfCheckStatement, ScrapedOnChainVotes, SessionIndex, SessionInfo,
-	ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature,
+use polkadot_primitives::{
+	v1::{
+		AuthorityDiscoveryId, CandidateEvent, CommittedCandidateReceipt, CoreState,
+		GroupRotationInfo, Id as ParaId, InboundDownwardMessage, InboundHrmpMessage,
+		OccupiedCoreAssumption, PersistedValidationData, ScrapedOnChainVotes, SessionIndex,
+		ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature,
+	},
+	v2::{PvfCheckStatement, SessionInfo},
 };
 use sp_core::testing::TaskExecutor;
 use std::{
@@ -508,6 +511,7 @@ fn dummy_session_info() -> SessionInfo {
 		n_delay_tranches: 2u32,
 		no_show_slots: 0u32,
 		needed_approvals: 1u32,
+		active_validator_indices: vec![],
 	}
 }
 #[test]
diff --git a/polkadot/node/network/availability-distribution/src/tests/mock.rs b/polkadot/node/network/availability-distribution/src/tests/mock.rs
index d9e61d9c48..469fd04efc 100644
--- a/polkadot/node/network/availability-distribution/src/tests/mock.rs
+++ b/polkadot/node/network/availability-distribution/src/tests/mock.rs
@@ -22,10 +22,13 @@ use sp_keyring::Sr25519Keyring;
 
 use polkadot_erasure_coding::{branches, obtain_chunks_v1 as obtain_chunks};
 use polkadot_node_primitives::{AvailableData, BlockData, ErasureChunk, PoV, Proof};
-use polkadot_primitives::v1::{
-	CandidateCommitments, CandidateDescriptor, CandidateHash, CommittedCandidateReceipt,
-	GroupIndex, Hash, HeadData, Id as ParaId, OccupiedCore, PersistedValidationData, SessionInfo,
-	ValidatorIndex,
+use polkadot_primitives::{
+	v1::{
+		CandidateCommitments, CandidateDescriptor, CandidateHash, CommittedCandidateReceipt,
+		GroupIndex, Hash, HeadData, Id as ParaId, OccupiedCore, PersistedValidationData,
+		ValidatorIndex,
+	},
+	v2::SessionInfo,
 };
 use polkadot_primitives_test_helpers::{
 	dummy_collator, dummy_collator_signature, dummy_hash, dummy_validation_code,
@@ -61,6 +64,7 @@ pub fn make_session_info() -> SessionInfo {
 		n_delay_tranches: 0,
 		no_show_slots: 0,
 		needed_approvals: 0,
+		active_validator_indices: Vec::new(),
 	}
 }
 
diff --git a/polkadot/node/network/availability-distribution/src/tests/state.rs b/polkadot/node/network/availability-distribution/src/tests/state.rs
index 267596a810..e9b81ee1aa 100644
--- a/polkadot/node/network/availability-distribution/src/tests/state.rs
+++ b/polkadot/node/network/availability-distribution/src/tests/state.rs
@@ -39,9 +39,9 @@ use polkadot_node_network_protocol::{
 	request_response::{v1, IncomingRequest, OutgoingRequest, Requests},
 };
 use polkadot_node_primitives::ErasureChunk;
-use polkadot_primitives::v1::{
-	CandidateHash, CoreState, GroupIndex, Hash, Id as ParaId, ScheduledCore, SessionInfo,
-	ValidatorIndex,
+use polkadot_primitives::{
+	v1::{CandidateHash, CoreState, GroupIndex, Hash, Id as ParaId, ScheduledCore, ValidatorIndex},
+	v2::SessionInfo,
 };
 use polkadot_subsystem::{
 	messages::{
diff --git a/polkadot/node/network/availability-recovery/src/lib.rs b/polkadot/node/network/availability-recovery/src/lib.rs
index 2b9169a54b..41298512f4 100644
--- a/polkadot/node/network/availability-recovery/src/lib.rs
+++ b/polkadot/node/network/availability-recovery/src/lib.rs
@@ -48,9 +48,12 @@ use polkadot_node_network_protocol::{
 };
 use polkadot_node_primitives::{AvailableData, ErasureChunk};
 use polkadot_node_subsystem_util::request_session_info;
-use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, BlakeTwo256, BlockNumber, CandidateHash, CandidateReceipt, GroupIndex,
-	Hash, HashT, SessionIndex, SessionInfo, ValidatorId, ValidatorIndex,
+use polkadot_primitives::{
+	v1::{
+		AuthorityDiscoveryId, BlakeTwo256, BlockNumber, CandidateHash, CandidateReceipt,
+		GroupIndex, Hash, HashT, SessionIndex, ValidatorId, ValidatorIndex,
+	},
+	v2::SessionInfo,
 };
 use polkadot_subsystem::{
 	errors::RecoveryError,
diff --git a/polkadot/node/network/availability-recovery/src/tests.rs b/polkadot/node/network/availability-recovery/src/tests.rs
index 021b7d49a8..3e0359cd07 100644
--- a/polkadot/node/network/availability-recovery/src/tests.rs
+++ b/polkadot/node/network/availability-recovery/src/tests.rs
@@ -220,6 +220,7 @@ impl TestState {
 					n_delay_tranches: 0,
 					no_show_slots: 0,
 					needed_approvals: 0,
+					active_validator_indices: vec![],
 				}))).unwrap();
 			}
 		);
diff --git a/polkadot/node/network/collator-protocol/src/collator_side/tests.rs b/polkadot/node/network/collator-protocol/src/collator_side/tests.rs
index e1d6fd093a..dd20c73fa2 100644
--- a/polkadot/node/network/collator-protocol/src/collator_side/tests.rs
+++ b/polkadot/node/network/collator-protocol/src/collator_side/tests.rs
@@ -32,9 +32,12 @@ use sp_runtime::traits::AppVerify;
 use polkadot_node_network_protocol::{our_view, request_response::IncomingRequest, view};
 use polkadot_node_primitives::BlockData;
 use polkadot_node_subsystem_util::TimeoutExt;
-use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, CollatorPair, GroupRotationInfo, ScheduledCore, SessionIndex,
-	SessionInfo, ValidatorId, ValidatorIndex,
+use polkadot_primitives::{
+	v1::{
+		AuthorityDiscoveryId, CollatorPair, GroupRotationInfo, ScheduledCore, SessionIndex,
+		ValidatorId, ValidatorIndex,
+	},
+	v2::SessionInfo,
 };
 use polkadot_primitives_test_helpers::TestCandidateBuilder;
 use polkadot_subsystem::{
@@ -110,6 +113,7 @@ impl Default for TestState {
 				n_delay_tranches: 0,
 				no_show_slots: 0,
 				needed_approvals: 0,
+				active_validator_indices: vec![],
 			},
 			group_rotation_info,
 			validator_peer_id,
diff --git a/polkadot/node/network/dispute-distribution/src/tests/mock.rs b/polkadot/node/network/dispute-distribution/src/tests/mock.rs
index 6ca61f22cf..b5acb96edc 100644
--- a/polkadot/node/network/dispute-distribution/src/tests/mock.rs
+++ b/polkadot/node/network/dispute-distribution/src/tests/mock.rs
@@ -32,9 +32,12 @@ use sp_keyring::Sr25519Keyring;
 use sp_keystore::{SyncCryptoStore, SyncCryptoStorePtr};
 
 use polkadot_node_primitives::{DisputeMessage, SignedDisputeStatement};
-use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, CandidateHash, CandidateReceipt, Hash, SessionIndex, SessionInfo,
-	ValidatorId, ValidatorIndex,
+use polkadot_primitives::{
+	v1::{
+		AuthorityDiscoveryId, CandidateHash, CandidateReceipt, Hash, SessionIndex, ValidatorId,
+		ValidatorIndex,
+	},
+	v2::SessionInfo,
 };
 use polkadot_primitives_test_helpers::dummy_candidate_descriptor;
 
@@ -86,6 +89,7 @@ pub static ref MOCK_SESSION_INFO: SessionInfo =
 		n_delay_tranches: 0,
 		no_show_slots: 0,
 		needed_approvals: 0,
+		active_validator_indices: vec![],
 	};
 
 /// `SessionInfo` for the second session. (No more validators, but two more authorities.
@@ -105,6 +109,7 @@ pub static ref MOCK_NEXT_SESSION_INFO: SessionInfo =
 		n_delay_tranches: 0,
 		no_show_slots: 0,
 		needed_approvals: 0,
+		active_validator_indices: vec![],
 	};
 }
 
diff --git a/polkadot/node/network/dispute-distribution/src/tests/mod.rs b/polkadot/node/network/dispute-distribution/src/tests/mod.rs
index 07239fc552..a34b4bc203 100644
--- a/polkadot/node/network/dispute-distribution/src/tests/mod.rs
+++ b/polkadot/node/network/dispute-distribution/src/tests/mod.rs
@@ -41,8 +41,9 @@ use polkadot_node_network_protocol::{
 	IfDisconnected,
 };
 use polkadot_node_primitives::{CandidateVotes, UncheckedDisputeMessage};
-use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, CandidateHash, Hash, SessionIndex, SessionInfo,
+use polkadot_primitives::{
+	v1::{AuthorityDiscoveryId, CandidateHash, Hash, SessionIndex},
+	v2::SessionInfo,
 };
 use polkadot_subsystem::{
 	messages::{
diff --git a/polkadot/node/network/statement-distribution/src/tests.rs b/polkadot/node/network/statement-distribution/src/tests.rs
index 41263a6862..383f96fcc8 100644
--- a/polkadot/node/network/statement-distribution/src/tests.rs
+++ b/polkadot/node/network/statement-distribution/src/tests.rs
@@ -28,7 +28,7 @@ use polkadot_node_network_protocol::{
 };
 use polkadot_node_primitives::Statement;
 use polkadot_node_subsystem_test_helpers::mock::make_ferdie_keystore;
-use polkadot_primitives::v1::{SessionInfo, ValidationCode};
+use polkadot_primitives::{v1::ValidationCode, v2::SessionInfo};
 use polkadot_primitives_test_helpers::{dummy_committed_candidate_receipt, dummy_hash};
 use polkadot_subsystem::{
 	jaeger,
@@ -1851,5 +1851,6 @@ fn make_session_info(validators: Vec<Pair>, groups: Vec<Vec<u32>>) -> SessionInf
 		n_delay_tranches: 0,
 		no_show_slots: 0,
 		needed_approvals: 0,
+		active_validator_indices: Vec::new(),
 	}
 }
diff --git a/polkadot/node/overseer/src/lib.rs b/polkadot/node/overseer/src/lib.rs
index 36ffe54240..0a947506cd 100644
--- a/polkadot/node/overseer/src/lib.rs
+++ b/polkadot/node/overseer/src/lib.rs
@@ -71,7 +71,10 @@ use futures::{channel::oneshot, future::BoxFuture, select, Future, FutureExt, St
 use lru::LruCache;
 
 use client::{BlockImportNotification, BlockchainEvents, FinalityNotification};
-use polkadot_primitives::v1::{Block, BlockId, BlockNumber, Hash, ParachainHost};
+use polkadot_primitives::{
+	v1::{Block, BlockId, BlockNumber, Hash},
+	v2::ParachainHost,
+};
 use sp_api::{ApiExt, ProvideRuntimeApi};
 
 use polkadot_node_network_protocol::v1 as protocol_v1;
diff --git a/polkadot/node/primitives/src/disputes/message.rs b/polkadot/node/primitives/src/disputes/message.rs
index 94e609c30a..5c057e973b 100644
--- a/polkadot/node/primitives/src/disputes/message.rs
+++ b/polkadot/node/primitives/src/disputes/message.rs
@@ -23,11 +23,11 @@ use thiserror::Error;
 
 use parity_scale_codec::{Decode, Encode};
 
-use polkadot_primitives::v1::{
-	CandidateReceipt, DisputeStatement, SessionIndex, SessionInfo, ValidatorIndex,
-};
-
 use super::{InvalidDisputeVote, SignedDisputeStatement, ValidDisputeVote};
+use polkadot_primitives::{
+	v1::{CandidateReceipt, DisputeStatement, SessionIndex, ValidatorIndex},
+	v2::SessionInfo,
+};
 
 /// A dispute initiating/participating message that is guaranteed to have been built from signed
 /// statements.
diff --git a/polkadot/node/service/src/lib.rs b/polkadot/node/service/src/lib.rs
index fb35bd23c8..47a130451a 100644
--- a/polkadot/node/service/src/lib.rs
+++ b/polkadot/node/service/src/lib.rs
@@ -53,7 +53,7 @@ pub use sp_core::traits::SpawnNamed;
 #[cfg(feature = "full-node")]
 pub use {
 	polkadot_overseer::{Handle, Overseer, OverseerConnector, OverseerHandle},
-	polkadot_primitives::v1::ParachainHost,
+	polkadot_primitives::v2::ParachainHost,
 	relay_chain_selection::SelectRelayChain,
 	sc_client_api::AuxStore,
 	sp_authority_discovery::AuthorityDiscoveryApi,
diff --git a/polkadot/node/service/src/overseer.rs b/polkadot/node/service/src/overseer.rs
index f112da381c..520db8127d 100644
--- a/polkadot/node/service/src/overseer.rs
+++ b/polkadot/node/service/src/overseer.rs
@@ -34,7 +34,7 @@ use polkadot_overseer::{
 	OverseerConnector, OverseerHandle,
 };
 
-use polkadot_primitives::v1::ParachainHost;
+use polkadot_primitives::v2::ParachainHost;
 use sc_authority_discovery::Service as AuthorityDiscoveryService;
 use sc_client_api::AuxStore;
 use sc_keystore::LocalKeystore;
diff --git a/polkadot/node/subsystem-types/src/messages.rs b/polkadot/node/subsystem-types/src/messages.rs
index c88c8d6352..ecff4b2b1d 100644
--- a/polkadot/node/subsystem-types/src/messages.rs
+++ b/polkadot/node/subsystem-types/src/messages.rs
@@ -38,14 +38,17 @@ use polkadot_node_primitives::{
 	CollationSecondedSignal, DisputeMessage, ErasureChunk, PoV, SignedDisputeStatement,
 	SignedFullStatement, ValidationResult,
 };
-use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, BackedCandidate, BlockNumber, CandidateDescriptor, CandidateEvent,
-	CandidateHash, CandidateIndex, CandidateReceipt, CollatorId, CommittedCandidateReceipt,
-	CoreState, GroupIndex, GroupRotationInfo, Hash, Header as BlockHeader, Id as ParaId,
-	InboundDownwardMessage, InboundHrmpMessage, MultiDisputeStatementSet, OccupiedCoreAssumption,
-	PersistedValidationData, PvfCheckStatement, SessionIndex, SessionInfo,
-	SignedAvailabilityBitfield, SignedAvailabilityBitfields, ValidationCode, ValidationCodeHash,
-	ValidatorId, ValidatorIndex, ValidatorSignature,
+use polkadot_primitives::{
+	v1::{
+		AuthorityDiscoveryId, BackedCandidate, BlockNumber, CandidateDescriptor, CandidateEvent,
+		CandidateHash, CandidateIndex, CandidateReceipt, CollatorId, CommittedCandidateReceipt,
+		CoreState, GroupIndex, GroupRotationInfo, Hash, Header as BlockHeader, Id as ParaId,
+		InboundDownwardMessage, InboundHrmpMessage, MultiDisputeStatementSet,
+		OccupiedCoreAssumption, PersistedValidationData, SessionIndex, SignedAvailabilityBitfield,
+		SignedAvailabilityBitfields, ValidationCode, ValidationCodeHash, ValidatorId,
+		ValidatorIndex, ValidatorSignature,
+	},
+	v2::{PvfCheckStatement, SessionInfo},
 };
 use polkadot_statement_table::v1::Misbehavior;
 use std::{
diff --git a/polkadot/node/subsystem-util/src/lib.rs b/polkadot/node/subsystem-util/src/lib.rs
index b06ffe6ba6..99f9119e4d 100644
--- a/polkadot/node/subsystem-util/src/lib.rs
+++ b/polkadot/node/subsystem-util/src/lib.rs
@@ -49,11 +49,14 @@ use futures::{
 use parity_scale_codec::Encode;
 use pin_project::pin_project;
 
-use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, CandidateEvent, CommittedCandidateReceipt, CoreState, EncodeAs,
-	GroupIndex, GroupRotationInfo, Hash, Id as ParaId, OccupiedCoreAssumption,
-	PersistedValidationData, SessionIndex, SessionInfo, Signed, SigningContext, ValidationCode,
-	ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature,
+use polkadot_primitives::{
+	v1::{
+		AuthorityDiscoveryId, CandidateEvent, CommittedCandidateReceipt, CoreState, EncodeAs,
+		GroupIndex, GroupRotationInfo, Hash, Id as ParaId, OccupiedCoreAssumption,
+		PersistedValidationData, SessionIndex, Signed, SigningContext, ValidationCode,
+		ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature,
+	},
+	v2::SessionInfo,
 };
 use sp_application_crypto::AppKey;
 use sp_core::{traits::SpawnNamed, ByteArray};
diff --git a/polkadot/node/subsystem-util/src/rolling_session_window.rs b/polkadot/node/subsystem-util/src/rolling_session_window.rs
index 2ecf51d8df..f5cf11d261 100644
--- a/polkadot/node/subsystem-util/src/rolling_session_window.rs
+++ b/polkadot/node/subsystem-util/src/rolling_session_window.rs
@@ -20,7 +20,10 @@
 //! care about the state of particular blocks.
 
 pub use polkadot_node_primitives::{new_session_window_size, SessionWindowSize};
-use polkadot_primitives::v1::{Hash, SessionIndex, SessionInfo};
+use polkadot_primitives::{
+	v1::{Hash, SessionIndex},
+	v2::SessionInfo,
+};
 
 use futures::channel::oneshot;
 use polkadot_node_subsystem::{
@@ -288,6 +291,7 @@ mod tests {
 			n_delay_tranches: index as _,
 			no_show_slots: index as _,
 			needed_approvals: index as _,
+			active_validator_indices: Vec::new(),
 		}
 	}
 
diff --git a/polkadot/node/subsystem-util/src/runtime/mod.rs b/polkadot/node/subsystem-util/src/runtime/mod.rs
index 3a1e22a4cc..fc5a344649 100644
--- a/polkadot/node/subsystem-util/src/runtime/mod.rs
+++ b/polkadot/node/subsystem-util/src/runtime/mod.rs
@@ -26,10 +26,13 @@ use sp_core::crypto::ByteArray;
 use sp_keystore::{CryptoStore, SyncCryptoStorePtr};
 
 use polkadot_node_subsystem::{SubsystemContext, SubsystemSender};
-use polkadot_primitives::v1::{
-	CandidateEvent, CoreState, EncodeAs, GroupIndex, GroupRotationInfo, Hash, OccupiedCore,
-	SessionIndex, SessionInfo, Signed, SigningContext, UncheckedSigned, ValidationCode,
-	ValidationCodeHash, ValidatorId, ValidatorIndex,
+use polkadot_primitives::{
+	v1::{
+		CandidateEvent, CoreState, EncodeAs, GroupIndex, GroupRotationInfo, Hash, OccupiedCore,
+		SessionIndex, Signed, SigningContext, UncheckedSigned, ValidationCode, ValidationCodeHash,
+		ValidatorId, ValidatorIndex,
+	},
+	v2::SessionInfo,
 };
 
 use crate::{
diff --git a/polkadot/primitives/src/lib.rs b/polkadot/primitives/src/lib.rs
index 1c549da942..febcb175d0 100644
--- a/polkadot/primitives/src/lib.rs
+++ b/polkadot/primitives/src/lib.rs
@@ -21,3 +21,4 @@
 
 pub mod v0;
 pub mod v1;
+pub mod v2;
diff --git a/polkadot/primitives/src/v1/mod.rs b/polkadot/primitives/src/v1/mod.rs
index 003dc681d6..4719f9fa44 100644
--- a/polkadot/primitives/src/v1/mod.rs
+++ b/polkadot/primitives/src/v1/mod.rs
@@ -19,7 +19,7 @@
 use bitvec::vec::BitVec;
 use parity_scale_codec::{Decode, Encode};
 use scale_info::TypeInfo;
-use sp_std::{collections::btree_map::BTreeMap, prelude::*};
+use sp_std::prelude::*;
 
 use application_crypto::KeyTypeId;
 use inherents::InherentIdentifier;
@@ -984,86 +984,6 @@ impl ApprovalVote {
 	}
 }
 
-sp_api::decl_runtime_apis! {
-	/// The API for querying the state of parachains on-chain.
-	#[api_version(2)]
-	pub trait ParachainHost<H: Encode + Decode = Hash, N: Encode + Decode = BlockNumber> {
-		/// Get the current validators.
-		fn validators() -> Vec<ValidatorId>;
-
-		/// Returns the validator groups and rotation info localized based on the hypothetical child
-		///  of a block whose state  this is invoked on. Note that `now` in the `GroupRotationInfo`
-		/// should be the successor of the number of the block.
-		fn validator_groups() -> (Vec<Vec<ValidatorIndex>>, GroupRotationInfo<N>);
-
-		/// Yields information on all availability cores as relevant to the child block.
-		/// Cores are either free or occupied. Free cores can have paras assigned to them.
-		fn availability_cores() -> Vec<CoreState<H, N>>;
-
-		/// Yields the persisted validation data for the given `ParaId` along with an assumption that
-		/// should be used if the para currently occupies a core.
-		///
-		/// Returns `None` if either the para is not registered or the assumption is `Freed`
-		/// and the para already occupies a core.
-		fn persisted_validation_data(para_id: Id, assumption: OccupiedCoreAssumption)
-			-> Option<PersistedValidationData<H, N>>;
-
-		/// Returns the persisted validation data for the given `ParaId` along with the corresponding
-		/// validation code hash. Instead of accepting assumption about the para, matches the validation
-		/// data hash against an expected one and yields `None` if they're not equal.
-		fn assumed_validation_data(
-			para_id: Id,
-			expected_persisted_validation_data_hash: Hash,
-		) -> Option<(PersistedValidationData<H, N>, ValidationCodeHash)>;
-
-		/// Checks if the given validation outputs pass the acceptance criteria.
-		fn check_validation_outputs(para_id: Id, outputs: CandidateCommitments) -> bool;
-
-		/// Returns the session index expected at a child of the block.
-		///
-		/// This can be used to instantiate a `SigningContext`.
-		fn session_index_for_child() -> SessionIndex;
-
-		/// Get the session info for the given session, if stored.
-		fn session_info(index: SessionIndex) -> Option<SessionInfo>;
-
-		/// Fetch the validation code used by a para, making the given `OccupiedCoreAssumption`.
-		///
-		/// Returns `None` if either the para is not registered or the assumption is `Freed`
-		/// and the para already occupies a core.
-		fn validation_code(para_id: Id, assumption: OccupiedCoreAssumption)
-			-> Option<ValidationCode>;
-
-		/// Get the receipt of a candidate pending availability. This returns `Some` for any paras
-		/// assigned to occupied cores in `availability_cores` and `None` otherwise.
-		fn candidate_pending_availability(para_id: Id) -> Option<CommittedCandidateReceipt<H>>;
-
-		/// Get a vector of events concerning candidates that occurred within a block.
-		fn candidate_events() -> Vec<CandidateEvent<H>>;
-
-		/// Get all the pending inbound messages in the downward message queue for a para.
-		fn dmq_contents(
-			recipient: Id,
-		) -> Vec<InboundDownwardMessage<N>>;
-
-		/// Get the contents of all channels addressed to the given recipient. Channels that have no
-		/// messages in them are also included.
-		fn inbound_hrmp_channels_contents(recipient: Id) -> BTreeMap<Id, Vec<InboundHrmpMessage<N>>>;
-
-		/// Get the validation code from its hash.
-		fn validation_code_by_hash(hash: ValidationCodeHash) -> Option<ValidationCode>;
-
-		/// Scrape dispute relevant from on-chain, backing votes and resolved disputes.
-		fn on_chain_votes() -> Option<ScrapedOnChainVotes<H>>;
-
-		/// Submits a PVF pre-checking statement into the transaction pool.
-		fn submit_pvf_check_statement(stmt: PvfCheckStatement, signature: ValidatorSignature);
-
-		/// Returns code hashes of PVFs that require pre-checking by validators in the active set.
-		fn pvfs_require_precheck() -> Vec<ValidationCodeHash>;
-	}
-}
-
 /// Custom validity errors used in Polkadot while validating transactions.
 #[repr(u8)]
 pub enum ValidityError {
@@ -1393,31 +1313,6 @@ pub struct InherentData<HDR: HeaderT = Header> {
 	pub parent_header: HDR,
 }
 
-/// A statement from the specified validator whether the given validation code passes PVF
-/// pre-checking or not anchored to the given session index.
-#[derive(Encode, Decode, Clone, PartialEq, RuntimeDebug, TypeInfo)]
-pub struct PvfCheckStatement {
-	/// `true` if the subject passed pre-checking and `false` otherwise.
-	pub accept: bool,
-	/// The validation code hash that was checked.
-	pub subject: ValidationCodeHash,
-	/// The index of a session during which this statement is considered valid.
-	pub session_index: SessionIndex,
-	/// The index of the validator from which this statement originates.
-	pub validator_index: ValidatorIndex,
-}
-
-impl PvfCheckStatement {
-	/// Produce the payload used for signing this type of statement.
-	///
-	/// It is expected that it will be signed by the validator at `validator_index` in the
-	/// `session_index`.
-	pub fn signing_payload(&self) -> Vec<u8> {
-		const MAGIC: [u8; 4] = *b"VCPC"; // for "validation code pre-checking"
-		(MAGIC, self.accept, self.subject, self.session_index, self.validator_index).encode()
-	}
-}
-
 /// The maximum number of validators `f` which may safely be faulty.
 ///
 /// The total number of validators is `n = 3f + e` where `e in { 1, 2, 3 }`.
diff --git a/polkadot/primitives/src/v2/mod.rs b/polkadot/primitives/src/v2/mod.rs
new file mode 100644
index 0000000000..4fc2de2feb
--- /dev/null
+++ b/polkadot/primitives/src/v2/mod.rs
@@ -0,0 +1,220 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! `V2` Primitives.
+
+use crate::v1;
+
+use parity_scale_codec::{Decode, Encode};
+use primitives::RuntimeDebug;
+use scale_info::TypeInfo;
+use sp_std::{collections::btree_map::BTreeMap, prelude::*};
+
+#[cfg(feature = "std")]
+use parity_util_mem::MallocSizeOf;
+
+/// Information about validator sets of a session.
+#[derive(Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
+#[cfg_attr(feature = "std", derive(PartialEq, MallocSizeOf))]
+pub struct SessionInfo {
+	/****** New in v2 *******/
+	/// All the validators actively participating in parachain consensus.
+	/// Indices are into the broader validator set.
+	pub active_validator_indices: Vec<v1::ValidatorIndex>,
+
+	/****** Old fields ******/
+	/// Validators in canonical ordering.
+	///
+	/// NOTE: There might be more authorities in the current session, than `validators` participating
+	/// in parachain consensus. See
+	/// [`max_validators`](https://github.com/paritytech/polkadot/blob/a52dca2be7840b23c19c153cf7e110b1e3e475f8/runtime/parachains/src/configuration.rs#L148).
+	///
+	/// `SessionInfo::validators` will be limited to to `max_validators` when set.
+	pub validators: Vec<v1::ValidatorId>,
+	/// Validators' authority discovery keys for the session in canonical ordering.
+	///
+	/// NOTE: The first `validators.len()` entries will match the corresponding validators in
+	/// `validators`, afterwards any remaining authorities can be found. This is any authorities not
+	/// participating in parachain consensus - see
+	/// [`max_validators`](https://github.com/paritytech/polkadot/blob/a52dca2be7840b23c19c153cf7e110b1e3e475f8/runtime/parachains/src/configuration.rs#L148)
+	#[cfg_attr(feature = "std", ignore_malloc_size_of = "outside type")]
+	pub discovery_keys: Vec<v1::AuthorityDiscoveryId>,
+	/// The assignment keys for validators.
+	///
+	/// NOTE: There might be more authorities in the current session, than validators participating
+	/// in parachain consensus. See
+	/// [`max_validators`](https://github.com/paritytech/polkadot/blob/a52dca2be7840b23c19c153cf7e110b1e3e475f8/runtime/parachains/src/configuration.rs#L148).
+	///
+	/// Therefore:
+	/// ```ignore
+	///		assignment_keys.len() == validators.len() && validators.len() <= discovery_keys.len()
+	///	```
+	pub assignment_keys: Vec<v1::AssignmentId>,
+	/// Validators in shuffled ordering - these are the validator groups as produced
+	/// by the `Scheduler` module for the session and are typically referred to by
+	/// `GroupIndex`.
+	pub validator_groups: Vec<Vec<v1::ValidatorIndex>>,
+	/// The number of availability cores used by the protocol during this session.
+	pub n_cores: u32,
+	/// The zeroth delay tranche width.
+	pub zeroth_delay_tranche_width: u32,
+	/// The number of samples we do of `relay_vrf_modulo`.
+	pub relay_vrf_modulo_samples: u32,
+	/// The number of delay tranches in total.
+	pub n_delay_tranches: u32,
+	/// How many slots (BABE / SASSAFRAS) must pass before an assignment is considered a
+	/// no-show.
+	pub no_show_slots: u32,
+	/// The number of validators needed to approve a block.
+	pub needed_approvals: u32,
+}
+
+impl From<v1::SessionInfo> for SessionInfo {
+	fn from(old: v1::SessionInfo) -> SessionInfo {
+		SessionInfo {
+			// new fields
+			active_validator_indices: Vec::new(),
+			// old fields
+			validators: old.validators,
+			discovery_keys: old.discovery_keys,
+			assignment_keys: old.assignment_keys,
+			validator_groups: old.validator_groups,
+			n_cores: old.n_cores,
+			zeroth_delay_tranche_width: old.zeroth_delay_tranche_width,
+			relay_vrf_modulo_samples: old.relay_vrf_modulo_samples,
+			n_delay_tranches: old.n_delay_tranches,
+			no_show_slots: old.no_show_slots,
+			needed_approvals: old.needed_approvals,
+		}
+	}
+}
+
+/// A statement from the specified validator whether the given validation code passes PVF
+/// pre-checking or not anchored to the given session index.
+#[derive(Encode, Decode, Clone, PartialEq, RuntimeDebug, TypeInfo)]
+pub struct PvfCheckStatement {
+	/// `true` if the subject passed pre-checking and `false` otherwise.
+	pub accept: bool,
+	/// The validation code hash that was checked.
+	pub subject: v1::ValidationCodeHash,
+	/// The index of a session during which this statement is considered valid.
+	pub session_index: v1::SessionIndex,
+	/// The index of the validator from which this statement originates.
+	pub validator_index: v1::ValidatorIndex,
+}
+
+impl PvfCheckStatement {
+	/// Produce the payload used for signing this type of statement.
+	///
+	/// It is expected that it will be signed by the validator at `validator_index` in the
+	/// `session_index`.
+	pub fn signing_payload(&self) -> Vec<u8> {
+		const MAGIC: [u8; 4] = *b"VCPC"; // for "validation code pre-checking"
+		(MAGIC, self.accept, self.subject, self.session_index, self.validator_index).encode()
+	}
+}
+
+sp_api::decl_runtime_apis! {
+	/// The API for querying the state of parachains on-chain.
+	#[api_version(2)]
+	pub trait ParachainHost<H: Encode + Decode = v1::Hash, N: Encode + Decode = v1::BlockNumber> {
+		/// Get the current validators.
+		fn validators() -> Vec<v1::ValidatorId>;
+
+		/// Returns the validator groups and rotation info localized based on the hypothetical child
+		///  of a block whose state  this is invoked on. Note that `now` in the `GroupRotationInfo`
+		/// should be the successor of the number of the block.
+		fn validator_groups() -> (Vec<Vec<v1::ValidatorIndex>>, v1::GroupRotationInfo<N>);
+
+		/// Yields information on all availability cores as relevant to the child block.
+		/// Cores are either free or occupied. Free cores can have paras assigned to them.
+		fn availability_cores() -> Vec<v1::CoreState<H, N>>;
+
+		/// Yields the persisted validation data for the given `ParaId` along with an assumption that
+		/// should be used if the para currently occupies a core.
+		///
+		/// Returns `None` if either the para is not registered or the assumption is `Freed`
+		/// and the para already occupies a core.
+		fn persisted_validation_data(para_id: v1::Id, assumption: v1::OccupiedCoreAssumption)
+			-> Option<v1::PersistedValidationData<H, N>>;
+
+		/// Returns the persisted validation data for the given `ParaId` along with the corresponding
+		/// validation code hash. Instead of accepting assumption about the para, matches the validation
+		/// data hash against an expected one and yields `None` if they're not equal.
+		fn assumed_validation_data(
+			para_id: v1::Id,
+			expected_persisted_validation_data_hash: v1::Hash,
+		) -> Option<(v1::PersistedValidationData<H, N>, v1::ValidationCodeHash)>;
+
+		/// Checks if the given validation outputs pass the acceptance criteria.
+		fn check_validation_outputs(para_id: v1::Id, outputs: v1::CandidateCommitments) -> bool;
+
+		/// Returns the session index expected at a child of the block.
+		///
+		/// This can be used to instantiate a `SigningContext`.
+		fn session_index_for_child() -> v1::SessionIndex;
+
+		/// Old method to fetch v1 session info.
+		#[changed_in(2)]
+		fn session_info(index: v1::SessionIndex) -> Option<v1::SessionInfo>;
+
+		/// Fetch the validation code used by a para, making the given `OccupiedCoreAssumption`.
+		///
+		/// Returns `None` if either the para is not registered or the assumption is `Freed`
+		/// and the para already occupies a core.
+		fn validation_code(para_id: v1::Id, assumption: v1::OccupiedCoreAssumption)
+			-> Option<v1::ValidationCode>;
+
+		/// Get the receipt of a candidate pending availability. This returns `Some` for any paras
+		/// assigned to occupied cores in `availability_cores` and `None` otherwise.
+		fn candidate_pending_availability(para_id: v1::Id) -> Option<v1::CommittedCandidateReceipt<H>>;
+
+		/// Get a vector of events concerning candidates that occurred within a block.
+		fn candidate_events() -> Vec<v1::CandidateEvent<H>>;
+
+		/// Get all the pending inbound messages in the downward message queue for a para.
+		fn dmq_contents(
+			recipient: v1::Id,
+		) -> Vec<v1::InboundDownwardMessage<N>>;
+
+		/// Get the contents of all channels addressed to the given recipient. Channels that have no
+		/// messages in them are also included.
+		fn inbound_hrmp_channels_contents(recipient: v1::Id) -> BTreeMap<v1::Id, Vec<v1::InboundHrmpMessage<N>>>;
+
+		/// Get the validation code from its hash.
+		fn validation_code_by_hash(hash: v1::ValidationCodeHash) -> Option<v1::ValidationCode>;
+
+		/// Scrape dispute relevant from on-chain, backing votes and resolved disputes.
+		fn on_chain_votes() -> Option<v1::ScrapedOnChainVotes<H>>;
+
+		/***** Added in v2 *****/
+
+		/// Get the session info for the given session, if stored.
+		///
+		/// NOTE: This function is only available since parachain host version 2.
+		fn session_info(index: v1::SessionIndex) -> Option<SessionInfo>;
+
+		/// Submits a PVF pre-checking statement into the transaction pool.
+		///
+		/// NOTE: This function is only available since parachain host version 2.
+		fn submit_pvf_check_statement(stmt: PvfCheckStatement, signature: v1::ValidatorSignature);
+
+		/// Returns code hashes of PVFs that require pre-checking by validators in the active set.
+		///
+		/// NOTE: This function is only available since parachain host version 2.
+		fn pvfs_require_precheck() -> Vec<v1::ValidationCodeHash>;
+	}
+}
diff --git a/polkadot/runtime/kusama/src/lib.rs b/polkadot/runtime/kusama/src/lib.rs
index 0275296c93..db55c0278c 100644
--- a/polkadot/runtime/kusama/src/lib.rs
+++ b/polkadot/runtime/kusama/src/lib.rs
@@ -22,11 +22,15 @@
 
 use pallet_transaction_payment::CurrencyAdapter;
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
-use primitives::v1::{
-	AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
-	CoreState, GroupRotationInfo, Hash, Id as ParaId, InboundDownwardMessage, InboundHrmpMessage,
-	Moment, Nonce, OccupiedCoreAssumption, PersistedValidationData, ScrapedOnChainVotes,
-	SessionInfo, Signature, ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex,
+use primitives::{
+	v1::{
+		AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
+		CoreState, GroupRotationInfo, Hash, Id as ParaId, InboundDownwardMessage,
+		InboundHrmpMessage, Moment, Nonce, OccupiedCoreAssumption, PersistedValidationData,
+		ScrapedOnChainVotes, Signature, ValidationCode, ValidationCodeHash, ValidatorId,
+		ValidatorIndex,
+	},
+	v2::SessionInfo,
 };
 use runtime_common::{
 	auctions, claims, crowdloan, impls::DealWithFees, paras_registrar, slots, xcm_sender,
@@ -1735,7 +1739,7 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 
-	impl primitives::v1::ParachainHost<Block, Hash, BlockNumber> for Runtime {
+	impl primitives::v2::ParachainHost<Block, Hash, BlockNumber> for Runtime {
 		fn validators() -> Vec<ValidatorId> {
 			parachains_runtime_api_impl::validators::<Runtime>()
 		}
@@ -1817,7 +1821,7 @@ sp_api::impl_runtime_apis! {
 		}
 
 		fn submit_pvf_check_statement(
-			stmt: primitives::v1::PvfCheckStatement,
+			stmt: primitives::v2::PvfCheckStatement,
 			signature: primitives::v1::ValidatorSignature,
 		) {
 			parachains_runtime_api_impl::submit_pvf_check_statement::<Runtime>(stmt, signature)
diff --git a/polkadot/runtime/parachains/src/paras.rs b/polkadot/runtime/parachains/src/paras.rs
index 56eb26f30a..601e280a5f 100644
--- a/polkadot/runtime/parachains/src/paras.rs
+++ b/polkadot/runtime/parachains/src/paras.rs
@@ -111,9 +111,12 @@ use bitvec::{order::Lsb0 as BitOrderLsb0, vec::BitVec};
 use frame_support::{pallet_prelude::*, traits::EstimateNextSessionRotation};
 use frame_system::pallet_prelude::*;
 use parity_scale_codec::{Decode, Encode};
-use primitives::v1::{
-	ConsensusLog, HeadData, Id as ParaId, PvfCheckStatement, SessionIndex, UpgradeGoAhead,
-	UpgradeRestriction, ValidationCode, ValidationCodeHash, ValidatorSignature,
+use primitives::{
+	v1::{
+		ConsensusLog, HeadData, Id as ParaId, SessionIndex, UpgradeGoAhead, UpgradeRestriction,
+		ValidationCode, ValidationCodeHash, ValidatorSignature,
+	},
+	v2::PvfCheckStatement,
 };
 use scale_info::TypeInfo;
 use sp_core::RuntimeDebug;
diff --git a/polkadot/runtime/parachains/src/runtime_api_impl/v1.rs b/polkadot/runtime/parachains/src/runtime_api_impl/v1.rs
index 561cfec594..480429bc54 100644
--- a/polkadot/runtime/parachains/src/runtime_api_impl/v1.rs
+++ b/polkadot/runtime/parachains/src/runtime_api_impl/v1.rs
@@ -21,12 +21,15 @@ use crate::{
 	configuration, dmp, hrmp, inclusion, initializer, paras, paras_inherent, scheduler,
 	session_info, shared,
 };
-use primitives::v1::{
-	AuthorityDiscoveryId, CandidateEvent, CommittedCandidateReceipt, CoreIndex, CoreOccupied,
-	CoreState, GroupIndex, GroupRotationInfo, Hash, Id as ParaId, InboundDownwardMessage,
-	InboundHrmpMessage, OccupiedCore, OccupiedCoreAssumption, PersistedValidationData,
-	PvfCheckStatement, ScheduledCore, ScrapedOnChainVotes, SessionIndex, SessionInfo,
-	ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature,
+use primitives::{
+	v1::{
+		AuthorityDiscoveryId, CandidateEvent, CommittedCandidateReceipt, CoreIndex, CoreOccupied,
+		CoreState, GroupIndex, GroupRotationInfo, Hash, Id as ParaId, InboundDownwardMessage,
+		InboundHrmpMessage, OccupiedCore, OccupiedCoreAssumption, PersistedValidationData,
+		ScheduledCore, ScrapedOnChainVotes, SessionIndex, ValidationCode, ValidationCodeHash,
+		ValidatorId, ValidatorIndex, ValidatorSignature,
+	},
+	v2::{PvfCheckStatement, SessionInfo},
 };
 use sp_runtime::traits::One;
 use sp_std::{collections::btree_map::BTreeMap, prelude::*};
diff --git a/polkadot/runtime/parachains/src/session_info.rs b/polkadot/runtime/parachains/src/session_info.rs
index 9c53357cb6..6bb924f033 100644
--- a/polkadot/runtime/parachains/src/session_info.rs
+++ b/polkadot/runtime/parachains/src/session_info.rs
@@ -24,17 +24,24 @@ use crate::{
 	util::{take_active_subset, take_active_subset_and_inactive},
 };
 use frame_support::{pallet_prelude::*, traits::OneSessionHandler};
-use primitives::v1::{AssignmentId, AuthorityDiscoveryId, SessionIndex, SessionInfo};
+use primitives::{
+	v1::{AssignmentId, AuthorityDiscoveryId, SessionIndex},
+	v2::SessionInfo,
+};
 use sp_std::vec::Vec;
 
 pub use pallet::*;
 
+pub mod migration;
+
 #[frame_support::pallet]
 pub mod pallet {
 	use super::*;
+	use frame_system::pallet_prelude::BlockNumberFor;
 
 	#[pallet::pallet]
 	#[pallet::generate_store(pub(super) trait Store)]
+	#[pallet::storage_version(migration::STORAGE_VERSION)]
 	pub struct Pallet<T>(_);
 
 	#[pallet::config]
@@ -66,6 +73,13 @@ pub mod pallet {
 	#[pallet::storage]
 	#[pallet::getter(fn session_info)]
 	pub(crate) type Sessions<T: Config> = StorageMap<_, Identity, SessionIndex, SessionInfo>;
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
+		fn on_runtime_upgrade() -> Weight {
+			migration::migrate_to_latest::<T>()
+		}
+	}
 }
 
 /// An abstraction for the authority discovery pallet
@@ -132,6 +146,7 @@ impl<T: Config> Pallet<T> {
 			n_delay_tranches,
 			no_show_slots,
 			needed_approvals,
+			active_validator_indices: active_set,
 		};
 		Sessions::<T>::insert(&new_session_index, &new_session_info);
 	}
diff --git a/polkadot/runtime/parachains/src/session_info/migration.rs b/polkadot/runtime/parachains/src/session_info/migration.rs
new file mode 100644
index 0000000000..07ef965dc9
--- /dev/null
+++ b/polkadot/runtime/parachains/src/session_info/migration.rs
@@ -0,0 +1,44 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! A module that is responsible for migration of storage.
+
+use crate::session_info::{Config, Pallet, Store};
+use frame_support::{pallet_prelude::*, traits::StorageVersion, weights::Weight};
+
+/// The current storage version.
+pub const STORAGE_VERSION: StorageVersion = StorageVersion::new(1);
+
+/// Migrates the pallet storage to the most recent version, checking and setting the `StorageVersion`.
+pub fn migrate_to_latest<T: Config>() -> Weight {
+	let mut weight = 0;
+	if StorageVersion::get::<Pallet<T>>() < 1 {
+		weight += migrate_to_v1::<T>();
+		StorageVersion::new(1).put::<Pallet<T>>();
+	}
+	weight
+}
+
+pub fn migrate_to_v1<T: Config>() -> Weight {
+	let mut vs = 0;
+
+	<Pallet<T> as Store>::Sessions::translate_values(|old: primitives::v1::SessionInfo| {
+		vs += 1;
+		Some(primitives::v2::SessionInfo::from(old))
+	});
+
+	T::DbWeight::get().reads_writes(vs, vs)
+}
diff --git a/polkadot/runtime/polkadot/src/lib.rs b/polkadot/runtime/polkadot/src/lib.rs
index 61196a9cfa..5851b2027a 100644
--- a/polkadot/runtime/polkadot/src/lib.rs
+++ b/polkadot/runtime/polkadot/src/lib.rs
@@ -54,11 +54,15 @@ use pallet_mmr_primitives as mmr;
 use pallet_session::historical as session_historical;
 use pallet_transaction_payment::{FeeDetails, RuntimeDispatchInfo};
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
-use primitives::v1::{
-	AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
-	CoreState, GroupRotationInfo, Hash, Id as ParaId, InboundDownwardMessage, InboundHrmpMessage,
-	Moment, Nonce, OccupiedCoreAssumption, PersistedValidationData, ScrapedOnChainVotes,
-	SessionInfo, Signature, ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex,
+use primitives::{
+	v1::{
+		AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
+		CoreState, GroupRotationInfo, Hash, Id as ParaId, InboundDownwardMessage,
+		InboundHrmpMessage, Moment, Nonce, OccupiedCoreAssumption, PersistedValidationData,
+		ScrapedOnChainVotes, Signature, ValidationCode, ValidationCodeHash, ValidatorId,
+		ValidatorIndex,
+	},
+	v2::SessionInfo,
 };
 use sp_core::{
 	u32_trait::{_1, _2, _3, _4, _5},
@@ -1702,7 +1706,7 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 
-	impl primitives::v1::ParachainHost<Block, Hash, BlockNumber> for Runtime {
+	impl primitives::v2::ParachainHost<Block, Hash, BlockNumber> for Runtime {
 		fn validators() -> Vec<ValidatorId> {
 			parachains_runtime_api_impl::validators::<Runtime>()
 		}
@@ -1784,7 +1788,7 @@ sp_api::impl_runtime_apis! {
 		}
 
 		fn submit_pvf_check_statement(
-			stmt: primitives::v1::PvfCheckStatement,
+			stmt: primitives::v2::PvfCheckStatement,
 			signature: primitives::v1::ValidatorSignature,
 		) {
 			parachains_runtime_api_impl::submit_pvf_check_statement::<Runtime>(stmt, signature)
diff --git a/polkadot/runtime/rococo/src/lib.rs b/polkadot/runtime/rococo/src/lib.rs
index cecaf5d12c..72a3929706 100644
--- a/polkadot/runtime/rococo/src/lib.rs
+++ b/polkadot/runtime/rococo/src/lib.rs
@@ -35,12 +35,14 @@ use pallet_mmr_primitives as mmr;
 use pallet_session::historical as session_historical;
 use pallet_transaction_payment::{CurrencyAdapter, FeeDetails, RuntimeDispatchInfo};
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
-use primitives::v1::{
-	AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
-	CoreState, GroupRotationInfo, Hash, Id, InboundDownwardMessage, InboundHrmpMessage, Moment,
-	Nonce, OccupiedCoreAssumption, PersistedValidationData, PvfCheckStatement, ScrapedOnChainVotes,
-	SessionInfo as SessionInfoData, Signature, ValidationCode, ValidationCodeHash, ValidatorId,
-	ValidatorIndex, ValidatorSignature,
+use primitives::{
+	v1::{
+		AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
+		CoreState, GroupRotationInfo, Hash, Id, InboundDownwardMessage, InboundHrmpMessage, Moment,
+		Nonce, OccupiedCoreAssumption, PersistedValidationData, ScrapedOnChainVotes, Signature,
+		ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature,
+	},
+	v2::{PvfCheckStatement, SessionInfo as SessionInfoData},
 };
 use runtime_common::{
 	assigned_slots, auctions, crowdloan, impls::ToAuthor, paras_registrar, paras_sudo_wrapper,
@@ -1293,7 +1295,7 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 
-	impl primitives::v1::ParachainHost<Block, Hash, BlockNumber> for Runtime {
+	impl primitives::v2::ParachainHost<Block, Hash, BlockNumber> for Runtime {
 		fn validators() -> Vec<ValidatorId> {
 			runtime_api_impl::validators::<Runtime>()
 		}
diff --git a/polkadot/runtime/test-runtime/src/lib.rs b/polkadot/runtime/test-runtime/src/lib.rs
index 35fab9ec95..217ca8146d 100644
--- a/polkadot/runtime/test-runtime/src/lib.rs
+++ b/polkadot/runtime/test-runtime/src/lib.rs
@@ -44,12 +44,15 @@ use pallet_mmr_primitives as mmr;
 use pallet_session::historical as session_historical;
 use pallet_transaction_payment::{FeeDetails, RuntimeDispatchInfo};
 use polkadot_runtime_parachains::reward_points::RewardValidatorsWithEraPoints;
-use primitives::v1::{
-	AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
-	CoreState, GroupRotationInfo, Hash as HashT, Id as ParaId, InboundDownwardMessage,
-	InboundHrmpMessage, Moment, Nonce, OccupiedCoreAssumption, PersistedValidationData,
-	ScrapedOnChainVotes, SessionInfo as SessionInfoData, Signature, ValidationCode,
-	ValidationCodeHash, ValidatorId, ValidatorIndex,
+use primitives::{
+	v1::{
+		AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
+		CoreState, GroupRotationInfo, Hash as HashT, Id as ParaId, InboundDownwardMessage,
+		InboundHrmpMessage, Moment, Nonce, OccupiedCoreAssumption, PersistedValidationData,
+		ScrapedOnChainVotes, Signature, ValidationCode, ValidationCodeHash, ValidatorId,
+		ValidatorIndex,
+	},
+	v2::SessionInfo as SessionInfoData,
 };
 use runtime_common::{
 	claims, paras_sudo_wrapper, BlockHashCount, BlockLength, BlockWeights, SlowAdjustingFeeUpdate,
@@ -796,7 +799,7 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 
-	impl primitives::v1::ParachainHost<Block, Hash, BlockNumber> for Runtime {
+	impl primitives::v2::ParachainHost<Block, Hash, BlockNumber> for Runtime {
 		fn validators() -> Vec<ValidatorId> {
 			runtime_impl::validators::<Runtime>()
 		}
@@ -876,7 +879,7 @@ sp_api::impl_runtime_apis! {
 		}
 
 		fn submit_pvf_check_statement(
-			stmt: primitives::v1::PvfCheckStatement,
+			stmt: primitives::v2::PvfCheckStatement,
 			signature: primitives::v1::ValidatorSignature,
 		) {
 			runtime_impl::submit_pvf_check_statement::<Runtime>(stmt, signature)
diff --git a/polkadot/runtime/westend/src/lib.rs b/polkadot/runtime/westend/src/lib.rs
index c399b26299..4a0494c11e 100644
--- a/polkadot/runtime/westend/src/lib.rs
+++ b/polkadot/runtime/westend/src/lib.rs
@@ -22,11 +22,15 @@
 
 use pallet_transaction_payment::CurrencyAdapter;
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
-use primitives::v1::{
-	AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
-	CoreState, GroupRotationInfo, Hash, Id as ParaId, InboundDownwardMessage, InboundHrmpMessage,
-	Moment, Nonce, OccupiedCoreAssumption, PersistedValidationData, ScrapedOnChainVotes,
-	SessionInfo, Signature, ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex,
+use primitives::{
+	v1::{
+		AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
+		CoreState, GroupRotationInfo, Hash, Id as ParaId, InboundDownwardMessage,
+		InboundHrmpMessage, Moment, Nonce, OccupiedCoreAssumption, PersistedValidationData,
+		ScrapedOnChainVotes, Signature, ValidationCode, ValidationCodeHash, ValidatorId,
+		ValidatorIndex,
+	},
+	v2::SessionInfo,
 };
 use runtime_common::{
 	assigned_slots, auctions, crowdloan, impls::ToAuthor, paras_registrar, paras_sudo_wrapper,
@@ -1306,7 +1310,7 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 
-	impl primitives::v1::ParachainHost<Block, Hash, BlockNumber> for Runtime {
+	impl primitives::v2::ParachainHost<Block, Hash, BlockNumber> for Runtime {
 		fn validators() -> Vec<ValidatorId> {
 			parachains_runtime_api_impl::validators::<Runtime>()
 		}
@@ -1388,7 +1392,7 @@ sp_api::impl_runtime_apis! {
 		}
 
 		fn submit_pvf_check_statement(
-			stmt: primitives::v1::PvfCheckStatement,
+			stmt: primitives::v2::PvfCheckStatement,
 			signature: primitives::v1::ValidatorSignature,
 		) {
 			parachains_runtime_api_impl::submit_pvf_check_statement::<Runtime>(stmt, signature)