diff --git a/packages/api/src/beacon/routes/beacon/block.ts b/packages/api/src/beacon/routes/beacon/block.ts
index 7c6e9c67c56b..2c141e3bdefd 100644
--- a/packages/api/src/beacon/routes/beacon/block.ts
+++ b/packages/api/src/beacon/routes/beacon/block.ts
@@ -12,8 +12,9 @@ import {
   SignedBlindedBeaconBlock,
   SignedBlockContents,
   sszTypesFor,
+  BeaconBlockBody,
 } from "@lodestar/types";
-import {ForkName, ForkPreExecution, isForkBlobs, isForkExecution} from "@lodestar/params";
+import {ForkName, ForkPreElectra, ForkPreExecution, isForkBlobs, isForkExecution} from "@lodestar/params";
 import {Endpoint, RequestCodec, RouteDefinitions, Schema} from "../../../utils/index.js";
 import {EmptyMeta, EmptyResponseCodec, EmptyResponseData, WithVersion} from "../../../utils/codecs.js";
 import {
@@ -26,7 +27,6 @@ import {
 import {getExecutionForkTypes, toForkName} from "../../../utils/fork.js";
 import {fromHeaders} from "../../../utils/headers.js";
 import {WireFormat} from "../../../utils/wireFormat.js";
-import {AttestationList, AttestationListPhase0} from "./pool.js";
 
 // See /packages/api/src/routes/index.ts for reasoning and instructions to add new routes
 
@@ -101,7 +101,7 @@ export type Endpoints = {
     "GET",
     BlockArgs,
     {params: {block_id: string}},
-    AttestationListPhase0,
+    BeaconBlockBody<ForkPreElectra>["attestations"],
     ExecutionOptimisticAndFinalizedMeta
   >;
 
@@ -113,7 +113,7 @@ export type Endpoints = {
     "GET",
     BlockArgs,
     {params: {block_id: string}},
-    AttestationList,
+    BeaconBlockBody["attestations"],
     ExecutionOptimisticFinalizedAndVersionMeta
   >;
 
diff --git a/packages/api/src/beacon/routes/beacon/pool.ts b/packages/api/src/beacon/routes/beacon/pool.ts
index 2f4ffcbb1c67..497bdfe98a17 100644
--- a/packages/api/src/beacon/routes/beacon/pool.ts
+++ b/packages/api/src/beacon/routes/beacon/pool.ts
@@ -1,8 +1,8 @@
 /* eslint-disable @typescript-eslint/naming-convention */
 import {ValueOf} from "@chainsafe/ssz";
 import {ChainForkConfig} from "@lodestar/config";
-import {ForkSeq} from "@lodestar/params";
-import {phase0, capella, CommitteeIndex, Slot, ssz, electra} from "@lodestar/types";
+import {ForkPreElectra, ForkSeq, isForkElectra} from "@lodestar/params";
+import {phase0, capella, CommitteeIndex, Slot, ssz, electra, AttesterSlashing} from "@lodestar/types";
 import {Schema, Endpoint, RouteDefinitions} from "../../../utils/index.js";
 import {
   ArrayOf,
@@ -171,7 +171,7 @@ export type Endpoints = {
    */
   submitPoolAttesterSlashings: Endpoint<
     "POST",
-    {attesterSlashing: phase0.AttesterSlashing},
+    {attesterSlashing: AttesterSlashing<ForkPreElectra>},
     {body: unknown},
     EmptyResponseData,
     EmptyMeta
@@ -262,9 +262,7 @@ export function getDefinitions(config: ChainForkConfig): RouteDefinitions<Endpoi
         schema: {query: {slot: Schema.Uint, committee_index: Schema.Uint}},
       },
       resp: {
-        data: WithVersion((fork) =>
-          ForkSeq[fork] >= ForkSeq.electra ? AttestationListTypeElectra : AttestationListTypePhase0
-        ),
+        data: WithVersion((fork) => (isForkElectra(fork) ? AttestationListTypeElectra : AttestationListTypePhase0)),
         meta: VersionCodec,
       },
     },
@@ -283,7 +281,7 @@ export function getDefinitions(config: ChainForkConfig): RouteDefinitions<Endpoi
       req: EmptyRequestCodec,
       resp: {
         data: WithVersion((fork) =>
-          ForkSeq[fork] >= ForkSeq.electra ? AttesterSlashingListTypeElectra : AttesterSlashingListTypePhase0
+          isForkElectra(fork) ? AttesterSlashingListTypeElectra : AttesterSlashingListTypePhase0
         ),
         meta: VersionCodec,
       },
@@ -346,11 +344,8 @@ export function getDefinitions(config: ChainForkConfig): RouteDefinitions<Endpoi
           };
         },
         parseReqJson: ({body, headers}) => {
-          const versionHeader = fromHeaders(headers, MetaHeader.Version, false);
-          const fork =
-            versionHeader !== undefined
-              ? toForkName(versionHeader)
-              : config.getForkName(Number((body as {data: {slot: string}}[])[0]?.data.slot ?? 0));
+          const versionHeader = fromHeaders(headers, MetaHeader.Version, true);
+          const fork = toForkName(versionHeader);
 
           return {
             signedAttestations:
@@ -415,13 +410,8 @@ export function getDefinitions(config: ChainForkConfig): RouteDefinitions<Endpoi
           };
         },
         parseReqJson: ({body, headers}) => {
-          const versionHeader = fromHeaders(headers, MetaHeader.Version, false);
-          const fork =
-            versionHeader !== undefined
-              ? toForkName(versionHeader)
-              : config.getForkName(
-                  Number((body as {attestations1: {data: {slot: string}}})?.attestations1.data.slot ?? 0)
-                );
+          const versionHeader = fromHeaders(headers, MetaHeader.Version, true);
+          const fork = toForkName(versionHeader);
 
           return {
             attesterSlashing:
diff --git a/packages/api/src/beacon/routes/validator.ts b/packages/api/src/beacon/routes/validator.ts
index 9ce7595332bd..510160b2e027 100644
--- a/packages/api/src/beacon/routes/validator.ts
+++ b/packages/api/src/beacon/routes/validator.ts
@@ -912,15 +912,8 @@ export function getDefinitions(config: ChainForkConfig): RouteDefinitions<Endpoi
           };
         },
         parseReqJson: ({body, headers}) => {
-          const versionHeader = fromHeaders(headers, MetaHeader.Version, false);
-          const fork =
-            versionHeader !== undefined
-              ? toForkName(versionHeader)
-              : config.getForkName(
-                  Number(
-                    (body as {message: {aggregate: {data: {slot: string}}}}[])[0]?.message.aggregate.data.slot ?? 0
-                  )
-                );
+          const versionHeader = fromHeaders(headers, MetaHeader.Version, true);
+          const fork = toForkName(versionHeader);
 
           return {
             signedAggregateAndProofs:
diff --git a/packages/beacon-node/src/api/impl/beacon/pool/index.ts b/packages/beacon-node/src/api/impl/beacon/pool/index.ts
index 6f4d84ab659c..5a66ebfe174e 100644
--- a/packages/beacon-node/src/api/impl/beacon/pool/index.ts
+++ b/packages/beacon-node/src/api/impl/beacon/pool/index.ts
@@ -38,7 +38,7 @@ export function getBeaconPoolApi({
     async getPoolAttestationsV2({slot, committeeIndex}) {
       // Already filtered by slot
       let attestations = chain.aggregatedAttestationPool.getAll(slot);
-      const fork = chain.config.getForkName(slot ?? attestations[0].data.slot) ?? ForkName.phase0;
+      const fork = chain.config.getForkName(slot ?? attestations[0]?.data.slot ?? chain.clock.currentSlot);
 
       if (committeeIndex !== undefined) {
         attestations = attestations.filter((attestation) => committeeIndex === attestation.data.index);
diff --git a/packages/validator/test/utils/apiStub.ts b/packages/validator/test/utils/apiStub.ts
index 508674811b2f..839e273a3c10 100644
--- a/packages/validator/test/utils/apiStub.ts
+++ b/packages/validator/test/utils/apiStub.ts
@@ -19,6 +19,7 @@ export function getApiClientStub(): ApiClientStub {
       publishBlindedBlockV2: vi.fn(),
       publishBlockV2: vi.fn(),
       submitPoolSyncCommitteeSignatures: vi.fn(),
+      submitPoolAttestations: vi.fn(),
       submitPoolAttestationsV2: vi.fn(),
     },
     validator: {