Along with iOS 15.5, Apple has rolled out a new App Store policy that allows developers to increase the subscription price without taking users' consent. Going forward, people who use paid applications or services from the Apple App Store on iPhone/iPad might have to keep a watch on their email for information regarding any hikes, because if the hike is within the thresholds defined by Apple, the subscription will renew automatically.
Why does this matter? Back in the day, Apple users had the right to deny a price hike. Whenever a developer proposed a hike on what the user is already paying, the user had an option to accept it or deny it and keep using the application or the service for the same price. Now, developers can simply roll out a hike without taking permission from the users, and those who miss the email notification might end up paying more without even knowing about it.
On the official support page, Apple mentions that "If you have a subscription to an app that's making a price increase that meets these specific conditions, Apple will always notify you of an increase in advance. You'll be notified in multiple ways that include an email, push notification (if push notifications are enabled), and a message that you must acknowledge which is displayed within the app."
Instead of asking users whether they are comfortable paying the new price for the app/service they have been using, Apple will now ask whether they want to continue their subscription or not. Apple has already answered this in the announcement post, saying that the method leads to "some service being unintentionally interrupter for users and they must take steps to resubscribe within the app."
Apple mentions that developers "who offer subscriptions can increase the price of a subscription without interrupting service only under certain specific conditions." The condition implies that the increase or hike should not exceed USD $5 and 50% of the subscription price (non-annual) and USD $50 and 50% of for annual subscription price. However, Apple does mention that the price can be increased only once per year without users' consent, which should prevent any scams from happening.