Stripe : Shift my customer from one product's recurring price plan to the same product's new recurring price plan?

Question: How to shift my customer from one product's recurring price plan to the same product's new recurring price plan?

What I did:

a) Created a product Via API

curl https://api.stripe.com/v1/products \
  -u sk_test_xxxxxxxxxxxxxxxxxxxxxxxxxx: \
  -d name="Daily Subscription"

b) Created a price plan under this product:

curl https://api.stripe.com/v1/prices \
  -u sk_test_xxxxxxxxxxxxxxxxxxxxxxxxxx: \
  -d unit_amount=1000 \
  -d currency=usd \
  -d "recurring[interval]"=day \
  -d product=prod_xxxxxxxxxxx [I got it from the first API hit response]

c) Now I have created a customer:

curl https://api.stripe.com/v1/customers \
-u sk_test_xxxxxxxxxxxxxxxxxxxxxxxxxx: \
--email="alive-to-die@gmail.com"
--name="alive-to-die"

d) Bought plan by the customer:

curl https://api.stripe.com/v1/checkout/sessions \
  -u sk_test_xxxxxxxxxxxxxxxxxxxxxxxxxx: \
  --data-urlencode success_url="https://example.com/success" \
  -d "line_items[0][price]"=price_xxxxxxxxxxxxxx \   [I got it from price plan API hit response]
  -d "line_items[0][quantity]"=1 \
  -d mode=payment

e) Now the Admin of my site wants to update the plan price (Previously it was $10 per day now he wants it to be $12.5 per day), and the issue starts from here:

1. Since Stripe does not give the option to update the plan price once anyone subscribes to this plan, I am unable to update the existing plan price. As it is stated here: Update a plan

>You cannot change a plan's ID, amount, currency, or billing cycle.

2. Increasing the quantity to update the plan price is not an option here as 0.5 value can not be managed via quantity. (change from $10 to $12.5)

3. Deleting the price plan and creating a new price plan will not work as my old customer will still charge the old price. As it is stated here: Delete a plan

>Deleting plans means new subscribers can’t be added. Existing subscribers aren’t affected.

How to overcome this issue? How to bind my old customers with this new price plan?

Note: I have already created a new price plan under the same product successfully as well.

Please help me to achieve my goal.

Thanks

To shift your existing customer to the new price plan, you need to update their subscription in Stripe. Here's a step-by-step guide:

1. Retrieve the existing subscription for the customer using their customer_id. This can be done using the List subscriptions API. Please replace customer_id with the actual customer ID.

2. From the response JSON, get the subscription ID. Set the new items array with the new price ID you want to switch to:

3. Update the subscription with the new items array:

   curl https://api.stripe.com/v1/subscriptions/sub_ID \
   -u sk_test_...: \
   -X POST \
   -d "items[0][id]"="item_ID" \
   -d "items[0][price]"="new_price_ID" \
   -d "proration_behavior"="create_prorations"

In the above code snippet, replace sub_ID, item_ID, and new_price_ID with the actual subscription ID, item ID, and the new price ID respectively.

Please note that this method would prorate the subscription by default. If you do not want proration, you can change the proration_behavior to none.

After this, the customer would be subscribed to the new pricing plan. However, you may want to send communication, such as an email, informing the customer of the updated pricing.

More details can be found in this guide.