diff --git a/zerver/management/commands/enqueue_digest_emails.py b/zerver/management/commands/enqueue_digest_emails.py
index 9f6568c523..2fcf4e37c0 100644
--- a/zerver/management/commands/enqueue_digest_emails.py
+++ b/zerver/management/commands/enqueue_digest_emails.py
@@ -9,7 +9,7 @@ from django.conf import settings
 from django.core.management.base import BaseCommand
 
 from zerver.lib.queue import queue_json_publish
-from zerver.models import UserActivity, UserProfile, get_realm, Realm
+from zerver.models import UserActivity, UserProfile, Realm
 
 ## Logging setup ##
 
@@ -57,7 +57,7 @@ def queue_digest_recipient(user_profile, cutoff):
              "cutoff": cutoff.strftime('%s')}
     queue_json_publish("digest_emails", event, lambda event: None)
 
-def domains_for_this_deployment():
+def realms_for_this_deployment():
     # type: () -> List[str]
     if settings.ZILENCER_ENABLED:
         # Voyager deployments don't have a Deployment entry.
@@ -70,18 +70,18 @@ def domains_for_this_deployment():
         except Deployment.DoesNotExist:
             raise ValueError("digest: Unable to determine deployment.")
 
-        return [r.domain for r in deployment.realms.all()]
+        return [r.string_id for r in deployment.realms.all()]
     # Voyager and development.
     return []
 
-def should_process_digest(domain, deployment_domains):
+def should_process_digest(realm_str, deployment_realms):
     # type: (str, List[str]) -> bool
-    if domain in settings.SYSTEM_ONLY_REALMS:
+    if realm_str in settings.SYSTEM_ONLY_REALMS:
         # Don't try to send emails to system-only realms
         return False
     if settings.PRODUCTION and not settings.VOYAGER:
         # zulip.com or staging.zulip.com
-        return domain in deployment_domains
+        return realm_str in deployment_realms
     return True
 
 class Command(BaseCommand):
@@ -97,16 +97,13 @@ in a while.
         if datetime.datetime.utcnow().weekday() not in VALID_DIGEST_DAYS:
             return
 
-        deployment_domains = domains_for_this_deployment()
+        deployment_realms = realms_for_this_deployment()
         for realm in Realm.objects.filter(deactivated=False, show_digest_email=True):
-            domain = realm.domain
-            if not should_process_digest(domain, deployment_domains):
+            if not should_process_digest(realm.string_id, deployment_realms):
                 continue
 
-            string_id = realm.string_id
             user_profiles = UserProfile.objects.filter(
-                realm=get_realm(string_id), is_active=True, is_bot=False,
-                enable_digest_emails=True)
+                realm=realm, is_active=True, is_bot=False, enable_digest_emails=True)
 
             for user_profile in user_profiles:
                 cutoff = last_business_day()
diff --git a/zerver/models.py b/zerver/models.py
index a636f83047..846cc6a3ad 100644
--- a/zerver/models.py
+++ b/zerver/models.py
@@ -270,7 +270,7 @@ def get_unique_open_realm():
     # On production installations, the (usually "zulip.com") system
     # realm is an empty realm just used for system bots, so don't
     # include it in this accounting.
-    realms = realms.exclude(domain__in=settings.SYSTEM_ONLY_REALMS)
+    realms = realms.exclude(string_id__in=settings.SYSTEM_ONLY_REALMS)
     if len(realms) != 1:
         return None
     realm = realms[0]
diff --git a/zerver/tests/tests.py b/zerver/tests/tests.py
index 1001932f6b..57943e37bc 100644
--- a/zerver/tests/tests.py
+++ b/zerver/tests/tests.py
@@ -2283,7 +2283,7 @@ class TestOpenRealms(ZulipTestCase):
         mit_realm.save()
         self.assertTrue(completely_open(mit_realm))
         self.assertEqual(get_unique_open_realm(), None)
-        with self.settings(SYSTEM_ONLY_REALMS={"zulip.com"}):
+        with self.settings(SYSTEM_ONLY_REALMS={"zulip"}):
             self.assertEqual(get_unique_open_realm(), mit_realm)
         mit_realm.restricted_to_domain = True
         mit_realm.save()
diff --git a/zproject/settings.py b/zproject/settings.py
index fa506f0621..f08ea30aba 100644
--- a/zproject/settings.py
+++ b/zproject/settings.py
@@ -185,7 +185,7 @@ DEFAULT_SETTINGS = {'TWITTER_CONSUMER_KEY': '',
                     'REALM_CREATION_LINK_VALIDITY_DAYS': 7,
                     'TERMS_OF_SERVICE': None,
                     'TOS_VERSION': None,
-                    'SYSTEM_ONLY_REALMS': {"zulip.com"},
+                    'SYSTEM_ONLY_REALMS': {"zulip"},
                     'FIRST_TIME_TOS_TEMPLATE': None,
                     'USING_PGROONGA': False,
                     'POST_MIGRATION_CACHE_FLUSHING': False,