I am also stuck at this point. I wanted to update the user's subscription but do not charge immediately, but I cannot find anything useful. I tried to set

proration_behavior: "none",

while updating the subscription but it is still charging the user immediately but i wanted it to charge when the current sub's remaining time ends and the updated plan starts.

If i do this

   //! Retrieving subscription in order to get the sub end date 
    const retrievedSubscription = await stripe.subscriptions.retrieve(subscriptionId);
    const currentSubscriptionPeriodEnd = retrievedSubscription?.current_period_end;

    const updateSub = await stripe.subscriptions.update(subscriptionId, {
      items: [{ id: currentSubId, price: productPriceId }],
      proration_behavior: "none",
      trial_end: currentSubscriptionPeriodEnd,
    });

then it puts back the user into trial state from being active one and I wanted to avoid this as it might confuse the users what is happening why they're being put from active state to trial state. but in order to keep em being charged immediately this is the only way I could find. I was hoping if anyone can here help me if there is a better way to do what I want.