diff --git a/subworkflow/ndppp_prep_cal.cwl b/subworkflow/ndppp_prep_cal.cwl
index 3d8080893246e1f2b0e547bf9391adc11270e8f3..c422e063e44d10bf4e14ce2027f76eed38f08b70 100644
--- a/subworkflow/ndppp_prep_cal.cwl
+++ b/subworkflow/ndppp_prep_cal.cwl
@@ -241,3 +241,5 @@ steps:
     'sbg:y': -55.93873977661133
 requirements:
   - class: SubworkflowFeatureRequirement
+  - class: StepInputExpressionRequirement
+  - class: InlineJavascriptRequirement