diff --git a/controller.py b/controller.py
index 7f4c00b..8ef457d 100644
--- a/controller.py
+++ b/controller.py
@@ -22,7 +22,6 @@
 
 from core.app_server import (
     cdn_url_for,
-    feed_response,
     load_pagination_from_request,
     HeartbeatController,
     Pagination,
@@ -68,6 +67,7 @@
 from core.util.opds_writer import OPDSMessage
 from core.util.problem_detail import ProblemDetail
 from core.util.string_helpers import base64
+from core.util.flask_util import OPDSFeedResponse
 
 from coverage_provider import (
     IdentifierResolutionCoverageProvider,
@@ -484,7 +484,7 @@ def updates_feed(self, metadata_identifier):
             collection, **url_params
         )
 
-        return feed_response(update_feed)
+        return OPDSFeedResponse(update_feed)
 
     def add_catalog_size_to_feed(self, feed, collection):
         """Add an <opensearch:totalResults> tag to `feed`
@@ -547,7 +547,7 @@ def add_items(self, metadata_identifier):
             precomposed_entries=messages
         )
 
-        return feed_response(addition_feed)
+        return OPDSFeedResponse(addition_feed)
 
     def add_with_metadata(self, metadata_identifier):
         """Adds identifiers with their metadata to a Collection's catalog"""
@@ -636,7 +636,7 @@ def add_with_metadata(self, metadata_identifier):
             precomposed_entries=messages
         )
 
-        return feed_response(addition_feed)
+        return OPDSFeedResponse(addition_feed)
 
     def metadata_needed_for(self, metadata_identifier):
         """Returns identifiers in the collection that could benefit from
@@ -696,7 +696,7 @@ def metadata_needed_for(self, metadata_identifier):
             'metadata_needed_for', collection
         )
 
-        return feed_response(request_feed)
+        return OPDSFeedResponse(request_feed)
 
     def remove_items(self, metadata_identifier):
         """Removes identifiers from a Collection's catalog"""
@@ -749,7 +749,7 @@ def remove_items(self, metadata_identifier):
             precomposed_entries=messages
         )
 
-        return feed_response(removal_feed)
+        return OPDSFeedResponse(removal_feed)
 
     def _in_catalog_subset(self, collection, identifiers_by_urn):
         """Helper method to find a subset of identifiers that
diff --git a/core b/core
index aa1f8b9..a19e86e 160000
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit aa1f8b9e46fb2444a7a8a9b0776000fa3118631c
+Subproject commit a19e86efce6061548108a9164877277d12d4c195
diff --git a/coverage_utils.py b/coverage_utils.py
index e16872f..1cae636 100644
--- a/coverage_utils.py
+++ b/coverage_utils.py
@@ -44,7 +44,7 @@ def from_db(cls, _db, **kwargs):
                 )
                 mirror = None
         mirrors = { ExternalIntegrationLink.COVERS : mirror,
-                    ExternalIntegrationLink.BOOKS : None }
+                    ExternalIntegrationLink.OPEN_ACCESS_BOOKS : None }
         return cls.from_metadata_source(
             mirrors=mirrors, **kwargs
         )
diff --git a/requirements.txt b/requirements.txt
index 7df5095..12a5200 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -24,7 +24,8 @@ money
 pymarc
 accept-types
 watchtower # for cloudwatch logging
-pyspellchecker
+pyspellchecker==0.5.6
+parameterized
 
 # nltk is a textblob dependency, and this is the last release that supports Python 2
 nltk==3.4.5
diff --git a/tests/test_coverage_utils.py b/tests/test_coverage_utils.py
index 97addf4..5b0ac0e 100644
--- a/tests/test_coverage_utils.py
+++ b/tests/test_coverage_utils.py
@@ -71,7 +71,7 @@ def test_from_db(self):
 
         # But the MirrorUploader is only to be used for book covers. The
         # metadata wrangler ignores the books themselves.
-        eq_(None, mirrors[ExternalIntegrationLink.BOOKS])
+        eq_(None, mirrors[ExternalIntegrationLink.OPEN_ACCESS_BOOKS])
 
 
 class TestMetadataWranglerBibliographicCoverageProvider(S3UploaderTest):
diff --git a/tests/test_overdrive.py b/tests/test_overdrive.py
index 92586b9..45bff93 100644
--- a/tests/test_overdrive.py
+++ b/tests/test_overdrive.py
@@ -3,6 +3,7 @@
     eq_,
     set_trace,
 )
+import urllib
 from core.metadata_layer import ReplacementPolicy
 from core.s3 import MockS3Uploader
 from core.testing import (
@@ -52,10 +53,10 @@ def test_replacement_policy_uses_provided_mirror(self):
 
         # Now let's try looking up a specific identifier through 'Overdrive'.
         identifier = self._identifier(
-            Identifier.OVERDRIVE_ID, "3896665d-9d81-4cac-bd43-ffc5066de1f5"
+            identifier_type=Identifier.OVERDRIVE_ID,
+            foreign_id="3896665d-9d81-4cac-bd43-ffc5066de1f5"
         )
 
-
         body = self.data_file("overdrive/overdrive_metadata.json")
         provider.api.queue_response(200, {}, body)
 
@@ -79,9 +80,9 @@ def test_replacement_policy_uses_provided_mirror(self):
 
         # The URLs for the Resource objects are our S3 URLs, not Overdrive's
         # URLs.
-        expect = "Overdrive/Overdrive+ID/%s" % identifier.identifier
+        expect = "Overdrive/Overdrive ID/%s" % identifier.identifier
         for url in [full.mirror_url, thumbnail.mirror_url]:
-            assert expect in url
+            assert urllib.quote(expect) in url
         assert "/scaled/" in thumbnail.mirror_url
         assert "/scaled/" not in full.mirror_url