After several postponements, the social network said in a blog post that Twitter Blue is available now. Users who pay $8 a month will received a check mark in a blue badge next to their profile pictures and will be able to edit tweets, among other perks. 

Twitter said it will take “a number of other steps to detect and prevent impersonation,” including a requirement that users have a valid phone number attached to their account. Users who change their user name or photo will also lose their check mark “until those changes are reviewed by Twitter.”

“Accounts found to be breaking our rules may be suspended without a refund,” the blog reads.

Before billionaire Elon Musk took the company private in late October, Twitter verified accounts with a blue badge as a way to distinguish prominent users, or those at risk of being impersonated, including celebrities, musicians and journalists. But the process of getting verified was also unclear, and Musk has criticized it as a “lords & peasants system.” 

But a first attempt at the pay-for-verification system led to widespread impersonation when users who bought check marks changed their user names to those of prominent brands and people, including Musk. The verification process was temporarily suspended as the company tried to figure out how to fix the issue. 

Musk is also taking a subtle shot at Apple Inc. as part of Twitter Blue’s relaunch. The company will charge users $11 per month if they subscribe through the Twitter app for Apple’s iOS, an effort to recoup fees collected by Apple for in-app purchases. Musk has repeatedly complained about those fees, calling them a “de facto global tax on the internet.”

Users who don’t pay for Twitter Blue will lose their verification badges “in a few months,” Musk tweeted Monday, though he has made similar statements before.

The San Francisco-based company said it will also start offering different colored check marks, including a gold one for businesses and a gray one for political accounts.