Twitter has launched a subscription service allowing users to buy blue-tick verification for a monthly fee of $7.99 in a major change under its new owner, Elon Musk. The system was designed to help users identify authentic and influential users on the platform, including government figures, sports stars, entertainment figures, journalists and major brands and organisations. But in an update to Apple iOS devices on Saturday, the social media company said any users who “sign up now” to its premium “Twitter Blue” service for $7.99 a month will get a blue tick. Available in the UK, as well as the …