diff --git a/packages/projection/src/operators/certificates/withCertificates.ts b/packages/projection/src/operators/certificates/withCertificates.ts
index ee5cbce4653..de0eeadea56 100644
--- a/packages/projection/src/operators/certificates/withCertificates.ts
+++ b/packages/projection/src/operators/certificates/withCertificates.ts
@@ -4,7 +4,7 @@ import { WithRolledBackEvents } from '../withRolledBackEvents';
 import { projectorOperator } from '../utils';
 
 export interface CertificatePointer {
-  blockHeight: Cardano.BlockNo;
+  slot: Cardano.Slot;
   txIndex: number;
   certIndex: number;
 }
@@ -23,7 +23,7 @@ export interface WithCertificates {
 
 const blockCertificates = ({
   block: {
-    header: { blockNo },
+    header: { slot },
     body
   }
 }: RollForwardEvent) =>
@@ -31,8 +31,8 @@ const blockCertificates = ({
     certificates.map((certificate, certIndex) => ({
       certificate,
       pointer: {
-        blockHeight: blockNo,
         certIndex,
+        slot,
         txIndex
       }
     }))
diff --git a/packages/projection/test/operators/certificates/withCertificates.test.ts b/packages/projection/test/operators/certificates/withCertificates.test.ts
index c5dbac1de31..7a850345b14 100644
--- a/packages/projection/test/operators/certificates/withCertificates.test.ts
+++ b/packages/projection/test/operators/certificates/withCertificates.test.ts
@@ -9,7 +9,7 @@ import {
 } from '../../../src';
 import { createTestScheduler } from '@cardano-sdk/util-dev';
 
-const rollForwardEvent = (blockNo: Cardano.BlockNo, txs: Cardano.Certificate[][]) =>
+const rollForwardEvent = (slot: Cardano.Slot, txs: Cardano.Certificate[][]) =>
   ({
     block: {
       body: txs.map(
@@ -18,7 +18,7 @@ const rollForwardEvent = (blockNo: Cardano.BlockNo, txs: Cardano.Certificate[][]
             body: { certificates }
           } as Cardano.TxAlonzo)
       ),
-      header: { blockNo }
+      header: { slot }
     },
     eventType: ChainSyncEventType.RollForward
   } as RollForwardEvent);
@@ -26,12 +26,12 @@ const rollForwardEvent = (blockNo: Cardano.BlockNo, txs: Cardano.Certificate[][]
 const rollBackwardEvent = (blocks: Cardano.Certificate[][][]) =>
   ({
     eventType: ChainSyncEventType.RollBackward,
-    rolledBackEvents: blocks.map((txs, blockNo) => ({
+    rolledBackEvents: blocks.map((txs, slot) => ({
       block: {
         body: txs.map((certificates) => ({
           body: { certificates }
         })),
-        header: { blockNo }
+        header: { slot }
       }
     }))
   } as RollBackwardEvent<WithRolledBackEvents>);
@@ -58,24 +58,24 @@ describe('withCertificates', () => {
             {
               certificate: certificates[0][0],
               pointer: {
-                blockHeight: 1,
                 certIndex: 0,
+                slot: 1,
                 txIndex: 0
               }
             },
             {
               certificate: certificates[1][0],
               pointer: {
-                blockHeight: 1,
                 certIndex: 0,
+                slot: 1,
                 txIndex: 1
               }
             },
             {
               certificate: certificates[1][1],
               pointer: {
-                blockHeight: 1,
                 certIndex: 1,
+                slot: 1,
                 txIndex: 1
               }
             }
@@ -102,24 +102,24 @@ describe('withCertificates', () => {
             {
               certificate: certificates[1][1],
               pointer: {
-                blockHeight: 0,
                 certIndex: 1,
+                slot: 0,
                 txIndex: 1
               }
             },
             {
               certificate: certificates[1][0],
               pointer: {
-                blockHeight: 0,
                 certIndex: 0,
+                slot: 0,
                 txIndex: 1
               }
             },
             {
               certificate: certificates[0][0],
               pointer: {
-                blockHeight: 0,
                 certIndex: 0,
+                slot: 0,
                 txIndex: 0
               }
             }
diff --git a/packages/projection/test/operators/certificates/withStakePools.test.ts b/packages/projection/test/operators/certificates/withStakePools.test.ts
index 4299c43f8c0..6c6220a1c31 100644
--- a/packages/projection/test/operators/certificates/withStakePools.test.ts
+++ b/packages/projection/test/operators/certificates/withStakePools.test.ts
@@ -48,7 +48,7 @@ describe('withStakePools', () => {
         } else {
           // delete all updates and retirements <= current tip
           const belowOrAtTip = ({ source }: WithCertificateSource) =>
-            evt.tip !== 'origin' && source.blockHeight <= evt.tip.blockNo;
+            evt.tip !== 'origin' && source.slot <= evt.tip.slot;
           for (const [_, stakePool] of stakePools) {
             stakePool.updates = stakePool.updates.filter(belowOrAtTip);
             stakePool.retirements = stakePool.retirements.filter(belowOrAtTip);