The long-rumoured Twitter paid subscription service might come to an end soon as the company just listed its subscription service on app stores under the name Blue.

The service is priced at £2.49 in the UK and $2.99 in the US on Apple Store and is not yet accessible to the public. On Google Play, the app is tagged with “in-app purchase” but does not list the pricing plan.

Jane Manchun Wong, an independent researcher who first reported the listing and claimed to be the first user to test the service, easier in her tweets reported functions including an “undo” button to recall a tweet seconds after it is posted, “collections” to allow users to create their own separate lists of tweets instead of relying on a single bookmark list, as well as a mode to make reading threads.

Twitter has not made any direct comment regarding this listing. The company told BBC that increasing “revenue durability” is its primary objective. It does plan to experiment with ways other than advertising to diversify revenue from this year onwards.