It is now possible to create and add a membership fee discount coupon to your application form.
Go to membership settings and create a coupon. This coupon can be in discount or fixed amount format. Make sure that this coupon's ID is different than the ones you previously created.
After you create a coupon all you need to do is enable credit form on your application form. Your applicants will need to see the credit card page in order to apply the coupon.
You can now use your coupon after filling up the application form and choosing a paid membership plan.
The discount is only applicable for membership fees; if you have an application fee, you will not be able to use it for that.
Tip: Make sure you have paid membership plans to use this feature. Here's how to create membership plans.