diff --git a/composer.json b/composer.json
index f5d92fb..e5d51a8 100644
--- a/composer.json
+++ b/composer.json
@@ -28,7 +28,7 @@
         "localgovdrupal/localgov_directories": "^3.1",
         "localgovdrupal/localgov_events": "^3.0",
         "localgovdrupal/localgov_microsites_group": "^4.0",
-        "localgovdrupal/localgov_microsites_base": "^2.0",
+        "localgovdrupal/localgov_microsites_base": "^2.0.3",
         "localgovdrupal/localgov_microsites_colour_picker_fields": "^1.0.0-beta1",
         "localgovdrupal/localgov_news": "^2.3",
         "localgovdrupal/localgov_page": "^1.0.0-beta2",
diff --git a/localgov_microsites.info.yml b/localgov_microsites.info.yml
index abc3ee3..8e888e1 100644
--- a/localgov_microsites.info.yml
+++ b/localgov_microsites.info.yml
@@ -62,6 +62,7 @@ install:
   - localgov_microsites_group:localgov_microsites_group_webform
   - localgov_paragraphs:localgov_paragraphs_views
   - localgov_sa11y:localgov_sa11y
+  - localgov_base:localgov_base_helper
 
 themes:
   - localgov_microsites_base
diff --git a/localgov_microsites.install b/localgov_microsites.install
index 4869f77..f29c2ad 100644
--- a/localgov_microsites.install
+++ b/localgov_microsites.install
@@ -56,3 +56,18 @@ function localgov_microsites_update_10001() {
     $role->save();
   }
 }
+
+/**
+ * Update existing sites to enable the theme dependency module for base.
+ */
+function localgov_microsites_update_10002() {
+  // The theme dependency should have caused the module to exist, but lets not
+  // fail if it's not there, as this is just a helper. The theme will continue
+  // to work when updated later, but report the requirement.
+  if (\Drupal::service('theme_handler')->themeExists('localgov_base')) {
+    if (\Drupal::service('module_installer')->install(['localgov_base_helper'])) {
+      return t('Base theme helper module enabled.');
+    }
+    return t('LocalGov Base theme will require the LocalGov Base Helper module. Enable it manually when upgrading to version 1.7.0 or higher. Required by LocalGov Microsites Base 2.0.3');
+  }
+}