We are going to change the Variant property paper_weight_unit on 2021-03-04:

• basis weight will no longer be supported as a value - Any existing fields set as grammage will be converted to the equivalent metric unit gsm - gsm will be the only accepted value when creating or updating Variants from this date If you are creating or updating Variants now, please set paper_weight_unit to gsm and be prepared to handle this value in any API response which includes Variant information.