Step 1: Navigate to Memberium => Support => Updates and select version 4.0.3 from the dropdown

Step 2: Select “Install” from the below dropdown and click “Update” button
Step 3: Replace [memb_add_creditcard] with [memb_add_paymentmethod]. Please note – parameters in these two shortcodes have been changed – successurl is now redirect, set_default is now default, tag_ids is now tag_id. Cardtypes, failureurl, addonly, action_ids, goals parameters from [memb_add_creditcard] are no longer available in [memb_add_paymentmethod].