The iOS 11.2 update brought the much-awaited Apple Pay Cash features to iPhone and iPad users this week.

The Apple Pay improvements were announced during Apple’s Worldwide Developers Conference in June. Apple announced on Tuesday the features have rolled out to all users in the United States.

“Apple customers already use iMessage to communicate with friends and family, and now they can get paid right within those everyday conversations, or by just asking Siri to pay someone,” Apple said in its announcement. “They can use the debit and credit cards they already have added to Apple Pay, so there’s no need to install an app or create yet another account.”

However, the roll out of iOS 11.2 on Monday didn’t bring Apple Pay Cash to all users, which caused users to complain on social media.

Apple Pay Cash Vs. Square Cash and Venmo

With Apple Pay Cash, users can carry out person-to-person payments on iMessage with other Apple device owners, meaning they don’t have to download a separate app to do so. When users get paid, the money stays on the Apple Pay Cash card. Those funds can then be used to make purchases in stores or online, or users can transfer the money to their bank account. A three percent fee is applied when sending money through a credit card, while transferring cash from a debit card is free. The Apple Pay Cash feature allows users to view their transaction history, including person-to-person payments and purchases made in stores, apps and online, in the Wallet app.

The downside about Apple Pay person-to-person payments is that both users need to have an Apple Pay Cash account, which means funds can’t be sent to Android users. Apple Pay Cash is available in the US on iPhone SE, iPhone 6 and later, Apple Watch, iPad Pro, iPad (5th Generation), iPad Air 2 and iPad mini 3.

That could lead people to use other free apps, like Venmo and Square Cash to send money to those who have Android devices. Venmo, which is part of PayPal, allows users to send and receive money, regardless of whether they have an iPhone or Android. Users can link their bank account or debit card to the app for transactions. It also has some social aspects to it, since users can like or comment on transactions, and see their friends’ activity as well (if they choose to share it). Venmo users can find people they know on the app by using your friend's name, @username, QR code, phone, email or by syncing their Facebook or phone contacts.

Square Cash is another Apple Pay Cash rival. With the Cash app, people can send and receive money from friends instantly. Users can link their Visa, MasterCard, or Discover debit card to transfer money. Cash app users can save the money they receive in the app, or deposit it directly to their bank account.

Facebook, PayPal and Zelle, which works through bank apps, are other services that compete with Apple Pay Cash as well.