diff --git a/package.json b/package.json
index d2566809..9916cff7 100644
--- a/package.json
+++ b/package.json
@@ -16,7 +16,7 @@
     "lint": "yarn lint-prettier && yarn lint-eslint"
   },
   "dependencies": {
-    "@unocha/hpc-api-core": "github:UN-OCHA/hpc-api-core#e298382f38848370c6daa0ac86b2016eddbef356",
+    "@unocha/hpc-api-core": "github:UN-OCHA/hpc-api-core#242c7c8e88ee130695b987afc06589afd5408710",
     "apollo-server-hapi": "^3.12.0",
     "bunyan": "^1.8.15",
     "class-validator": "^0.14.0",
diff --git a/src/domain-services/flows/strategy/impl/get-flowIds-flow-from-nested-flow-filters-strategy-impl.ts b/src/domain-services/flows/strategy/impl/get-flowIds-flow-from-nested-flow-filters-strategy-impl.ts
index 154d7187..5a633684 100644
--- a/src/domain-services/flows/strategy/impl/get-flowIds-flow-from-nested-flow-filters-strategy-impl.ts
+++ b/src/domain-services/flows/strategy/impl/get-flowIds-flow-from-nested-flow-filters-strategy-impl.ts
@@ -1,4 +1,5 @@
 import { Service } from 'typedi';
+import { LegacyService } from '../../../legacy/legacy-service';
 import { ReportDetailService } from '../../../report-details/report-detail-service';
 import { type UniqueFlowEntity } from '../../model';
 import {
@@ -12,7 +13,10 @@ import { intersectUniqueFlowEntities } from './utils';
 export class GetFlowIdsFromNestedFlowFiltersStrategyImpl
   implements FlowIDSearchStrategy
 {
-  constructor(private readonly reportDetailService: ReportDetailService) {}
+  constructor(
+    private readonly reportDetailService: ReportDetailService,
+    private readonly legacyService: LegacyService
+  ) {}
 
   async search(
     args: FlowIdSearchStrategyArgs
@@ -41,15 +45,20 @@ export class GetFlowIdsFromNestedFlowFiltersStrategyImpl
         );
     }
 
-    // TODO: Get the flowIDs using 'legacyID'
-    // TODO: create model for that
-    // if(nestedFlowFilters?.legacyId) {
-    //   flowsLegacyId = await this.flowService.getFlowIDsFromSourceSystemID(
-    //     models,
-    //     databaseConnection,
-    //     nestedFlowFilters.sourceSystemId
-    //   );
-    // }
+    // Get the flowIDs using 'legacyID'
+    if (nestedFlowFilters?.legacyID) {
+      const flowID = await this.legacyService.getFlowIdFromLegacyId(
+        models,
+        nestedFlowFilters.legacyID
+      );
+
+      if (flowID) {
+        flowsLegacyId.push({
+          id: flowID,
+          versionID: 1,
+        });
+      }
+    }
 
     // Intersect the flowIDs from the nestedFlowFilters
     const flowIDsFromNestedFlowFilters: UniqueFlowEntity[] =
diff --git a/src/domain-services/legacy/legacy-service.ts b/src/domain-services/legacy/legacy-service.ts
new file mode 100644
index 00000000..060cf7fa
--- /dev/null
+++ b/src/domain-services/legacy/legacy-service.ts
@@ -0,0 +1,24 @@
+import { type Database } from '@unocha/hpc-api-core/src/db';
+import { type FlowId } from '@unocha/hpc-api-core/src/db/models/flow';
+import { createBrandedValue } from '@unocha/hpc-api-core/src/util/types';
+import { Service } from 'typedi';
+
+@Service()
+export class LegacyService {
+  async getFlowIdFromLegacyId(
+    models: Database,
+    legacyId: number
+  ): Promise<FlowId | null> {
+    const legacyEntry = await models.legacy.findOne({
+      where: {
+        legacyID: legacyId,
+        objectType: 'flow',
+      },
+    });
+
+    if (legacyEntry) {
+      return createBrandedValue(legacyEntry.objectID);
+    }
+    return null;
+  }
+}