diff --git a/steps/aoflag.cwl b/steps/aoflag.cwl
index 9de3ca31a494f8e4fb0390acc0e504f5baa0ff48..7dbf22c10f7194a8330e7b79540d8ee3988401ce 100644
--- a/steps/aoflag.cwl
+++ b/steps/aoflag.cwl
@@ -17,12 +17,12 @@ inputs:
     type: Directory[]
     doc: Input measurement set
   - id: concat_meta_ms
-    type: Directory
+    type: Directory[]
     doc: Input measurement set
 #    inputBinding:
 #      position: 0
   - id: concat_additional_ms
-    type: Directory
+    type: Directory[]
     doc: Input measurement set
   - id: verbose
     type: boolean?
diff --git a/steps/ms_concat.cwl b/steps/ms_concat.cwl
index 8c291c6e65210d01e907e89df29b34e582ff87ca..a09b3cc1ad24f3fe85cc9ebcfd8d2010a4b8d627 100644
--- a/steps/ms_concat.cwl
+++ b/steps/ms_concat.cwl
@@ -30,12 +30,12 @@ inputs:
       position: 2
 outputs:
   - id: concat_meta_ms
-    type: 'Directory'
+    type: 'Directory[]'
     outputBinding:
       glob: |
         workdir/$(inputs.msout)_[0-9*]
   - id: concat_additional_ms
-    type: 'Directory'
+    type: 'Directory[]'
     outputBinding:
       glob: |
         workdir/$(inputs.msout)_*_CONCAT