This script upgrades the price on active subscriptions on Stripe

upgradeSubPrice.php

<?
	// set price
	$newPricePlanId='price_1NsRt5Inbsdfsfddsf';
	$newPriceMonthly=39;

	$i=1;
	foreach($users as $user) {

		if(!$user['stripe_customer_id']) {
			echo "No Stripe customer id, maybe update in db?";
			echo "\n";
			continue;
		}

		// <get customer's active subscription>
			$subscriptions = $stripe->subscriptions->all([
				'customer'=>$user['stripe_customer_id'],
				'status'=>'active',
				'limit'=>1
			]);
		// </get customer's active subscription>

		if(!$subscriptions['data']) {
			echo "No active subscriptions, maybe update in db?";
			echo "\n";
			continue;
		}

		$subscription=$subscriptions['data'][0];
		$subscriptionItem=$subscriptions['data'][0]['items']['data'][0];
		$plan=$subscriptionItem['plan'];


		// don't upgrade user to new plan if their next billing cycle is too soon
		if($subscription['current_period_end']<strtotime("+30 days")) {
			echo "Next billing time is in ".timeAgoLong($subscription['current_period_end']).", so it's too soon, so skip for now";
			echo "\n";
			continue;
		}
		

		echo '#';
		echo $i;
		echo "\t";
		echo $user['email'];
		echo "\t";


		// <upgrade plan on Stripe>
			echo "Updating plan to $39/mo...";
			try {
				$stripe->subscriptions->update(
					$subscription['id'],
					[
						'items'=>[[
							'id'=>$subscriptionItem['id'],
							'plan'=>$newPricePlanId,
							'quantity'=>1
						]],
						'proration_behavior'=>'none'
					]
				);
			} catch(\Stripe\Exception\ApiErrorException $e) {
				echo "Stripe error: could not upgrade ".$e->getMessage();
				echo "\n";
				continue;
			}

			echo "Done!";
			echo "\n";
			echo 'https://dashboard.stripe.com/customers/'.$user['stripe_customer_id'];
			echo "\n";
		// </upgrade plan on Stripe>

		// <save new plan and price to db>
			$query=$usersDb->prepare("UPDATE users SET 
														mrr=:mrr,
														subscription_amount=:subscription_amount
													WHERE
														stripe_customer_id=:stripe_customer_id
			");
			$query->bindValue(':mrr',$newPriceMonthly);
			$query->bindValue(':subscription_amount',$newPriceMonthly);
			$query->execute();
		// </save new plan and price to db>

		// <email user here>
		// </email user here>

	}
?>