diff --git a/x-pack/plugins/apm/server/saved_objects/apm_indices.ts b/x-pack/plugins/apm/server/saved_objects/apm_indices.ts
index 4a3b0d32e9667cf..fe6650fb356ff9c 100644
--- a/x-pack/plugins/apm/server/saved_objects/apm_indices.ts
+++ b/x-pack/plugins/apm/server/saved_objects/apm_indices.ts
@@ -8,7 +8,6 @@
 import { SavedObjectsType } from 'src/core/server';
 import { i18n } from '@kbn/i18n';
 import { updateApmOssIndexPaths } from './migrations/update_apm_oss_index_paths';
-import { ApmIndicesConfigName } from '..';
 
 export interface APMIndices {
   apmIndices?: {
@@ -22,32 +21,14 @@ export interface APMIndices {
   isSpaceAware?: boolean;
 }
 
-const properties: {
-  apmIndices: {
-    properties: {
-      [Property in ApmIndicesConfigName]: { type: 'keyword' };
-    };
-  };
-  isSpaceAware: { type: 'boolean' };
-} = {
-  apmIndices: {
-    properties: {
-      sourcemap: { type: 'keyword' },
-      error: { type: 'keyword' },
-      onboarding: { type: 'keyword' },
-      span: { type: 'keyword' },
-      transaction: { type: 'keyword' },
-      metric: { type: 'keyword' },
-    },
-  },
-  isSpaceAware: { type: 'boolean' },
-};
-
 export const apmIndices: SavedObjectsType = {
   name: 'apm-indices',
   hidden: false,
   namespaceType: 'single',
-  mappings: { properties },
+  mappings: {
+    dynamic: false,
+    properties: {}, // several fields exist, but we don't need to search or aggregate on them, so we exclude them from the mappings
+  },
   management: {
     importableAndExportable: true,
     icon: 'apmApp',
@@ -61,5 +42,9 @@ export const apmIndices: SavedObjectsType = {
       const attributes = updateApmOssIndexPaths(doc.attributes);
       return { ...doc, attributes };
     },
+    '8.2.0': (doc) => {
+      // Any future changes on this structure should be also tested on migrateLegacyAPMIndicesToSpaceAware
+      return { ...doc, attributes: { apmIndices: doc.attributes } };
+    },
   },
 };
diff --git a/x-pack/plugins/apm/server/saved_objects/migrations/migrate_legacy_apm_indices_to_space_aware.test.ts b/x-pack/plugins/apm/server/saved_objects/migrations/migrate_legacy_apm_indices_to_space_aware.test.ts
index 404e08a6b112b14..71488ab007c6769 100644
--- a/x-pack/plugins/apm/server/saved_objects/migrations/migrate_legacy_apm_indices_to_space_aware.test.ts
+++ b/x-pack/plugins/apm/server/saved_objects/migrations/migrate_legacy_apm_indices_to_space_aware.test.ts
@@ -81,12 +81,14 @@ describe('migrateLegacyAPMIndicesToSpaceAware', () => {
             updated_at: '2022-02-22T14:17:10.584Z',
             version: 'WzE1OSwxXQ==',
             attributes: {
-              transaction: 'default-apm-*',
-              span: 'default-apm-*',
-              error: 'default-apm-*',
-              metric: 'default-apm-*',
-              sourcemap: 'default-apm-*',
-              onboarding: 'default-apm-*',
+              apmIndices: {
+                transaction: 'default-apm-*',
+                span: 'default-apm-*',
+                error: 'default-apm-*',
+                metric: 'default-apm-*',
+                sourcemap: 'default-apm-*',
+                onboarding: 'default-apm-*',
+              },
             },
             references: [],
             migrationVersion: {
@@ -154,12 +156,14 @@ describe('migrateLegacyAPMIndicesToSpaceAware', () => {
       }),
     });
     const attributes = {
-      transaction: 'space-apm-*',
-      span: 'space-apm-*',
-      error: 'space-apm-*',
-      metric: 'space-apm-*',
-      sourcemap: 'space-apm-*',
-      onboarding: 'space-apm-*',
+      apmIndices: {
+        transaction: 'space-apm-*',
+        span: 'space-apm-*',
+        error: 'space-apm-*',
+        metric: 'space-apm-*',
+        sourcemap: 'space-apm-*',
+        onboarding: 'space-apm-*',
+      },
     };
     const core = {
       savedObjects: {
@@ -197,7 +201,7 @@ describe('migrateLegacyAPMIndicesToSpaceAware', () => {
               type: APM_INDEX_SETTINGS_SAVED_OBJECT_TYPE,
               id: APM_INDEX_SETTINGS_SAVED_OBJECT_ID,
               initialNamespaces: [id],
-              attributes: { apmIndices: attributes, isSpaceAware: true },
+              attributes: { ...attributes, isSpaceAware: true },
             };
           })
       );
diff --git a/x-pack/plugins/apm/server/saved_objects/migrations/migrate_legacy_apm_indices_to_space_aware.ts b/x-pack/plugins/apm/server/saved_objects/migrations/migrate_legacy_apm_indices_to_space_aware.ts
index 130070b80ff14f8..3f97191a5b88a7d 100644
--- a/x-pack/plugins/apm/server/saved_objects/migrations/migrate_legacy_apm_indices_to_space_aware.ts
+++ b/x-pack/plugins/apm/server/saved_objects/migrations/migrate_legacy_apm_indices_to_space_aware.ts
@@ -19,9 +19,10 @@ import { APMIndices } from '../apm_indices';
 
 async function fetchLegacyAPMIndices(repository: ISavedObjectsRepository) {
   try {
-    const apmIndices = await repository.get<
-      Partial<ApmIndicesConfig & { isSpaceAware: boolean }>
-    >(APM_INDEX_SETTINGS_SAVED_OBJECT_TYPE, APM_INDEX_SETTINGS_SAVED_OBJECT_ID);
+    const apmIndices = await repository.get<Partial<APMIndices>>(
+      APM_INDEX_SETTINGS_SAVED_OBJECT_TYPE,
+      APM_INDEX_SETTINGS_SAVED_OBJECT_ID
+    );
     if (apmIndices.attributes.isSpaceAware) {
       // This has already been migrated to become space-aware
       return null;
@@ -59,8 +60,8 @@ export async function migrateLegacyAPMIndicesToSpaceAware({
       fields: ['name'], // to avoid fetching *all* fields
     });
 
-    const savedObjectAttributes: APMIndices = {
-      apmIndices: legacyAPMIndices.attributes,
+    const savedObjectAttributes = {
+      ...legacyAPMIndices.attributes,
       isSpaceAware: true,
     };