diff --git a/potx.inc b/potx.inc
index eed090f..2abd96e 100644
--- a/potx.inc
+++ b/potx.inc
@@ -2189,7 +2189,8 @@ function _potx_process_config_schema($schema_prefix, $schema_data) {
   }
   else {
     if ($type == 'sequence') {
-      _potx_process_config_schema($schema_prefix . '+sequence', $schema_data['sequence'][0]);
+      $sequence_schema = isset($schema_data['sequence'][0]) ? $schema_data['sequence'][0] : $schema_data['sequence'];
+      _potx_process_config_schema($schema_prefix . '+sequence', $sequence_schema);
       $_potx_processed_schema['types'][$schema_prefix] = 'sequence';
     }
     // If the element's type is in the "translatables" list, or it has a
diff --git a/tests/drupal8/config/install/test.settings.yml b/tests/drupal8/config/install/test.settings.yml
index 12f41be..c333f89 100644
--- a/tests/drupal8/config/install/test.settings.yml
+++ b/tests/drupal8/config/install/test.settings.yml
@@ -35,6 +35,9 @@ sequence_of_sequence:
   sq2:
     - id: 7
       description: 'Sequence of sequence - Description 2'
+bc_sequence:
+  - 'BC sequence item 1'
+  - 'BC sequence item 2'
 
 # tests for variables.schema.yml
 test_variable:
diff --git a/tests/drupal8/config/schema/test.schema.yml b/tests/drupal8/config/schema/test.schema.yml
index 53db26f..84299da 100644
--- a/tests/drupal8/config/schema/test.schema.yml
+++ b/tests/drupal8/config/schema/test.schema.yml
@@ -29,6 +29,8 @@ test.settings:
       type: typed_sequence
     sequence_of_sequence:
       type: sequence_of_sequence
+    bc_sequence:
+      type: bc_sequence
     test_variable:
       type: basic_variable
     parent_variable_test:
diff --git a/tests/drupal8/config/schema/test.sequences.schema.yml b/tests/drupal8/config/schema/test.sequences.schema.yml
index 5f7ba6c..db91a95 100644
--- a/tests/drupal8/config/schema/test.sequences.schema.yml
+++ b/tests/drupal8/config/schema/test.sequences.schema.yml
@@ -2,20 +2,24 @@ simple_sequence:
   type: sequence
   label: 'Test sequence'
   sequence:
-    - type: text
-      label: 'Test string in sequence'
+    type: text
+    label: 'Test string in sequence'
 typed_sequence:
   type: sequence
   sequence:
-    - type: simple_mapping
+    type: simple_mapping
 sequence_of_sequence:
   type: sequence
   sequence:
-    - type: sequence
-      sequence:
-        - type: mapping
-          mapping:
-            id:
-              type: integer
-            description:
-              type: text
+    type: sequence
+    sequence:
+      type: mapping
+      mapping:
+        id:
+          type: integer
+        description:
+          type: text
+bc_sequence:
+  type: sequence
+  sequence:
+    - type: label
diff --git a/tests/drupal8/config/schema/test.variables.schema.yml b/tests/drupal8/config/schema/test.variables.schema.yml
index 1d2b714..d9fb11f 100644
--- a/tests/drupal8/config/schema/test.variables.schema.yml
+++ b/tests/drupal8/config/schema/test.variables.schema.yml
@@ -16,7 +16,7 @@ variable.plugin.*:
 basic_variable:
   type: sequence
   sequence:
-    - type: variable.plugin.[plugin_id]
+    type: variable.plugin.[plugin_id]
 
 variable.text:
   type: text
@@ -34,7 +34,7 @@ parent_variable.*:
 key_variable:
   type: sequence
   sequence:
-    - type: variable.[%key]
+    type: variable.[%key]
 
 complex_variable:
   type: mapping
diff --git a/tests/potx.test b/tests/potx.test
index 30045e6..cdfc369 100644
--- a/tests/potx.test
+++ b/tests/potx.test
@@ -445,6 +445,8 @@ class PotxTestCase extends DrupalWebTestCase {
     $this->assertMsgID('Typed sequence - Item 2 code');
     $this->assertMsgID('Sequence of sequence - Description 1');
     $this->assertMsgID('Sequence of sequence - Description 2');
+    $this->assertMsgID('BC sequence item 1');
+    $this->assertMsgID('BC sequence item 2');
     $this->assertMsgID('Basic variable (text)');
     $this->assertMsgID('Parent variable (text)');
     $this->assertMsgID('Key variable (text)');