diff --git a/beacon_node/http_api/src/lib.rs b/beacon_node/http_api/src/lib.rs
index 6656485dceb..3adf84fee13 100644
--- a/beacon_node/http_api/src/lib.rs
+++ b/beacon_node/http_api/src/lib.rs
@@ -1834,18 +1834,35 @@ pub fn serve<T: BeaconChainTypes>(
                             .filter(|&att| query_filter(att.data()))
                             .cloned(),
                     );
-                    let slot = query
-                        .slot
-                        .or_else(|| {
-                            attestations
-                                .first()
-                                .map(|att| att.data().slot)
-                                .or_else(|| chain.slot_clock.now())
-                        })
-                        .ok_or(warp_utils::reject::custom_server_error(
-                            "unable to read slot clock".to_string(),
-                        ))?;
-                    let fork_name = chain.spec.fork_name_at_slot::<T::EthSpec>(slot);
+                    // Use the current slot to find the fork version, and convert all messages to the
+                    // current fork's format. This is to ensure consistent message types matching
+                    // `Eth-Consensus-Version`.
+                    let current_slot =
+                        chain
+                            .slot_clock
+                            .now()
+                            .ok_or(warp_utils::reject::custom_server_error(
+                                "unable to read slot clock".to_string(),
+                            ))?;
+                    let fork_name = chain.spec.fork_name_at_slot::<T::EthSpec>(current_slot);
+
+                    let attestations = if fork_name.electra_enabled() {
+                        attestations
+                            .into_iter()
+                            .map(|att| match att {
+                                Attestation::Base(a) => Ok(Attestation::Electra(a.try_into()?)),
+                                Attestation::Electra(a) => Ok(Attestation::Electra(a)),
+                            })
+                            .collect::<Result<Vec<_>, types::attestation::Error>>()
+                            .map_err(|e| {
+                                warp_utils::reject::custom_server_error(format!(
+                                    "could not convert base attestations to electra {e:?}"
+                                ))
+                            })?
+                    } else {
+                        attestations
+                    };
+
                     let res = fork_versioned_response(endpoint_version, fork_name, &attestations)?;
                     Ok(add_consensus_version_header(
                         warp::reply::json(&res).into_response(),
@@ -1914,14 +1931,30 @@ pub fn serve<T: BeaconChainTypes>(
              chain: Arc<BeaconChain<T>>| {
                 task_spawner.blocking_response_task(Priority::P1, move || {
                     let slashings = chain.op_pool.get_all_attester_slashings();
-                    let slot = slashings
-                        .first()
-                        .map(|slashing| slashing.attestation_1().data().slot)
-                        .or_else(|| chain.slot_clock.now())
-                        .ok_or(warp_utils::reject::custom_server_error(
-                            "unable to read slot clock".to_string(),
-                        ))?;
-                    let fork_name = chain.spec.fork_name_at_slot::<T::EthSpec>(slot);
+
+                    // Use the current slot to find the fork version, and convert all messages to the
+                    // current fork's format. This is to ensure consistent message types matching
+                    // `Eth-Consensus-Version`.
+                    let current_slot =
+                        chain
+                            .slot_clock
+                            .now()
+                            .ok_or(warp_utils::reject::custom_server_error(
+                                "unable to read slot clock".to_string(),
+                            ))?;
+                    let fork_name = chain.spec.fork_name_at_slot::<T::EthSpec>(current_slot);
+
+                    let slashings = if fork_name.electra_enabled() {
+                        slashings
+                            .into_iter()
+                            .map(|att| match att {
+                                AttesterSlashing::Base(a) => AttesterSlashing::Electra(a.into()),
+                                AttesterSlashing::Electra(a) => AttesterSlashing::Electra(a),
+                            })
+                            .collect::<Vec<_>>()
+                    } else {
+                        slashings
+                    };
                     let res = fork_versioned_response(endpoint_version, fork_name, &slashings)?;
                     Ok(add_consensus_version_header(
                         warp::reply::json(&res).into_response(),
diff --git a/consensus/types/src/attestation.rs b/consensus/types/src/attestation.rs
index 1ee6c437c90..f12f84a447d 100644
--- a/consensus/types/src/attestation.rs
+++ b/consensus/types/src/attestation.rs
@@ -26,6 +26,12 @@ pub enum Error {
     InvalidCommitteeIndex,
 }
 
+impl From<ssz_types::Error> for Error {
+    fn from(e: ssz_types::Error) -> Self {
+        Error::SszTypesError(e)
+    }
+}
+
 #[superstruct(
     variants(Base, Electra),
     variant_attributes(
@@ -416,6 +422,35 @@ impl<E: EthSpec> AttestationBase<E> {
     }
 }
 
+impl<E: EthSpec> TryFrom<AttestationBase<E>> for AttestationElectra<E> {
+    type Error = Error;
+    fn try_from(att: AttestationBase<E>) -> Result<Self, Self::Error> {
+        // Extend the aggregation bits list.
+        let aggregation_bits = att.extend_aggregation_bits()?;
+        let AttestationBase {
+            aggregation_bits: _,
+            mut data,
+            signature,
+        } = att;
+
+        // Set the committee index based on the index field.
+        let mut committee_bits: BitVector<E::MaxCommitteesPerSlot> = BitVector::default();
+        committee_bits
+            .set(data.index as usize, true)
+            .map_err(|_| Error::InvalidCommitteeIndex)?;
+
+        // Set the attestation data's index to zero.
+        data.index = 0;
+
+        Ok(Self {
+            aggregation_bits,
+            data,
+            committee_bits,
+            signature,
+        })
+    }
+}
+
 impl<E: EthSpec> SlotData for Attestation<E> {
     fn get_slot(&self) -> Slot {
         self.data().slot
diff --git a/consensus/types/src/attester_slashing.rs b/consensus/types/src/attester_slashing.rs
index f6aa654d445..18ab63ad44e 100644
--- a/consensus/types/src/attester_slashing.rs
+++ b/consensus/types/src/attester_slashing.rs
@@ -1,5 +1,5 @@
 use crate::indexed_attestation::{
-    IndexedAttestationBase, IndexedAttestationElectra, IndexedAttestationRef,
+    IndexedAttestation, IndexedAttestationBase, IndexedAttestationElectra, IndexedAttestationRef,
 };
 use crate::{test_utils::TestRandom, EthSpec};
 use derivative::Derivative;
@@ -161,6 +161,19 @@ impl<E: EthSpec> AttesterSlashing<E> {
     }
 }
 
+impl<E: EthSpec> From<AttesterSlashingBase<E>> for AttesterSlashingElectra<E> {
+    fn from(attester_slashing: AttesterSlashingBase<E>) -> Self {
+        let AttesterSlashingBase {
+            attestation_1,
+            attestation_2,
+        } = attester_slashing;
+        AttesterSlashingElectra {
+            attestation_1: IndexedAttestation::Base(attestation_1).to_electra(),
+            attestation_2: IndexedAttestation::Base(attestation_2).to_electra(),
+        }
+    }
+}
+
 impl<E: EthSpec> TestRandom for AttesterSlashing<E> {
     fn random_for_test(rng: &mut impl RngCore) -> Self {
         if rng.gen_bool(0.5) {