Popular social networking service Twitter is adding an edit button for published tweets, the platform’s most-requested feature to date. Users will have to pay for it, at least initially. Edit Tweet, which is being tested internally, will expand to a public test in the coming weeks, rolling out to a select subset of Twitter Blue subscribers who will have 30 minutes from publication to Edit Tweet, doing things like fixing typos and adding missing tags. Tweets that have been edited will carry a label that even those not participating in the test will see.

“Edited tweets will appear with an icon, timestamp, and label so it’s clear to readers that the original tweet has been modified. Tapping the label will take viewers to the tweet’s Edit History, which includes past versions of the tweet,” Twitter said in a blog post. The time limit and version history are seen as important: “they protect the integrity of the conversation and create a publicly accessible record of what was said,” Twitter explained.

Introduced in June in Australia and Canada for $3 per month, Twitter Blue expanded in November to the U.S. and New Zealand. Subscriptions currently cost $5 per month. Although “the test will be localized” to a single, unidentified country at first,” Twitter says it will make the feature more broadly available after learning how people use it.

“Like any new feature, we’re intentionally testing Edit Tweet with a smaller group to help us incorporate feedback” while working through any potential issues, including “how people might misuse the feature,” Twitter says, adding, “You can never be too careful.”

Twitter already offers Twitter Blue users a 30-second window to cancel a post, a feature called “Undo Tweet.” The two features will coexist, according to the company, which gave no word on when Edit Tweet might be introduced to its general population, quantified at 328 million worldwide users, according to Statista.

“There are some definite grey areas that arise as a result of the rollout of an edit button,” notes TechCrunch, which says that “for starters, it could potentially play a role in how Twitter gets appropriated by the media. These days, tweets — whether from companies, politicians, artists, businesspeople or just ordinary people — are often used as the basis of news stories. Making those tweets editable will put the onus on publishers to track a tweet to check if its content has been changed.”

How regulators will view an edited tweet that contains content that violates sovereign law is another potential minefield. The concept of editing tweets has been a matter of public discussion for some time, with debates raging as to whether it will result in harmful effects, including obfuscation and misinformation.