diff --git a/aio/src/app/documents/document.service.spec.ts b/aio/src/app/documents/document.service.spec.ts
index 756651c1ce..4acddefe7c 100644
--- a/aio/src/app/documents/document.service.spec.ts
+++ b/aio/src/app/documents/document.service.spec.ts
@@ -67,6 +67,30 @@ describe('DocumentService', () => {
       expect(latestDocument).toEqual(doc1);
     });
 
+    // HACK: PREPARE FOR CHANGING TO CASE-INSENSITIVE URLS
+    it('should attempt disambiguated document paths if the document is not found on the server', () => {
+      let currentDocument: DocumentContents|undefined;
+      const notFoundDoc = { id: FILE_NOT_FOUND_ID, contents: '<h1>Page Not Found</h1>' };
+      const { docService, logger } = getServices('missing/Doc-1');
+      docService.currentDocument.subscribe(doc => currentDocument = doc);
+
+      // Initial request return 404.
+      httpMock.expectOne({url: 'generated/docs/missing/Doc-1.json'}).flush(null, {status: 404, statusText: 'NOT FOUND'});
+      httpMock.expectOne({url: 'generated/docs/missing/d_oc-1.json'}).flush(null, {status: 404, statusText: 'NOT FOUND'});
+      httpMock.expectOne({url: 'generated/docs/missing/d_oc.json'}).flush(null, {status: 404, statusText: 'NOT FOUND'});
+      expect(logger.output.error).toEqual([
+        [jasmine.any(Error)]
+      ]);
+      expect(logger.output.error[0][0].message).toEqual(`Document file not found at 'missing/Doc-1'`);
+
+      // Subsequent request for not-found document.
+      logger.output.error = [];
+      httpMock.expectOne(CONTENT_URL_PREFIX + 'file-not-found.json').flush(notFoundDoc);
+      expect(logger.output.error).toEqual([]); // does not report repeated errors
+      expect(currentDocument).toEqual(notFoundDoc);
+    });
+    // END HACK: PREPARE FOR CHANGING TO CASE-INSENSITIVE URLS
+
     it('should emit the not-found document if the document is not found on the server', () => {
       let currentDocument: DocumentContents|undefined;
       const notFoundDoc = { id: FILE_NOT_FOUND_ID, contents: '<h1>Page Not Found</h1>' };
@@ -83,7 +107,7 @@ describe('DocumentService', () => {
       // Subsequent request for not-found document.
       logger.output.error = [];
       httpMock.expectOne(CONTENT_URL_PREFIX + 'file-not-found.json').flush(notFoundDoc);
-      expect(logger.output.error).toEqual([]); // does not report repeate errors
+      expect(logger.output.error).toEqual([]); // does not report repeated errors
       expect(currentDocument).toEqual(notFoundDoc);
     });
 
diff --git a/aio/src/app/documents/document.service.ts b/aio/src/app/documents/document.service.ts
index 168e6e71c8..9d521f3232 100644
--- a/aio/src/app/documents/document.service.ts
+++ b/aio/src/app/documents/document.service.ts
@@ -1,7 +1,7 @@
 import { Injectable } from '@angular/core';
 import { HttpClient, HttpErrorResponse } from '@angular/common/http';
 
-import { AsyncSubject, Observable, of } from 'rxjs';
+import { AsyncSubject, Observable, of, throwError } from 'rxjs';
 import { catchError, switchMap, tap } from 'rxjs/operators';
 
 import { DocumentContents } from './document-contents';
@@ -66,6 +66,20 @@ export class DocumentService {
             throw Error('Invalid data');
           }
         }),
+        // HACK: PREPARE FOR CHANGING TO CASE-INSENSITIVE URLS
+        catchError((error: HttpErrorResponse) => {
+          const encodedPath = encodeToLowercase(requestPath);
+          return error.status === 404 && encodedPath !== requestPath ?
+              this.http.get<DocumentContents>(encodedPath) :
+              throwError(error);
+        }),
+        catchError((error: HttpErrorResponse) => {
+          const disambiguatedPath = convertDisambiguatedPath(requestPath);
+          return error.status === 404 && disambiguatedPath !== requestPath ?
+              this.http.get<DocumentContents>(disambiguatedPath) :
+              throwError(error);
+        }),
+        // END HACK: PREPARE FOR CHANGING TO CASE-INSENSITIVE URLS
         catchError((error: HttpErrorResponse) => {
           return error.status === 404 ? this.getFileNotFoundDoc(id) : this.getErrorDoc(id, error);
         }),
@@ -97,3 +111,30 @@ export class DocumentService {
     });
   }
 }
+
+/**
+ * Encode the path to the content in a deterministic, reversible, case-insensitive form.
+ *
+ * This avoids collisions on case-insensitive file-systems.
+ *
+ * - Escape underscores (_) to double underscores (__).
+ * - Convert all uppercase letters to lowercase followed by an underscore.
+ */
+function encodeToLowercase(str: string): string {
+  return str.replace(/[A-Z_]/g, char => char.toLowerCase() + '_');
+}
+
+/**
+ * A temporary function to deal with a future change to URL disambiguation.
+ *
+ * Currently there are disambiguated URLs such as `INJECTOR-0` and `Injector-1`, which
+ * will attempt to load their document contents from `injector-0.json` and `injector-1.json`
+ * respectively. In a future version of the AIO app, the disambiguation will be changed to
+ * escape the upper-case characters instead.
+ *
+ * This function will be called if the current AIO is trying to request documents from a
+ * server that has been updated to use the new disambiguated URLs.
+ */
+function convertDisambiguatedPath(str: string): string {
+  return encodeToLowercase(str.replace(/-\d+\.json$/, '.json'));
+}
diff --git a/goldens/size-tracking/aio-payloads.json b/goldens/size-tracking/aio-payloads.json
index cbb7ae312c..94291ad955 100755
--- a/goldens/size-tracking/aio-payloads.json
+++ b/goldens/size-tracking/aio-payloads.json
@@ -3,7 +3,7 @@
     "master": {
       "uncompressed": {
         "runtime-es2015": 4619,
-        "main-es2015": 453172,
+        "main-es2015": 453855,
         "polyfills-es2015": 55210
       }
     }
@@ -12,7 +12,7 @@
     "master": {
       "uncompressed": {
         "runtime-es2015": 4619,
-        "main-es2015": 453394,
+        "main-es2015": 453981,
         "polyfills-es2015": 55291
       }
     }