Yeah, he also wrote The Thick of It which is probably the best comedy series I’ve ever seen. Another writer on that was Jesse Armstrong of Succession fame.
"If such change to Individual plans is to occur, we plan to grandfather-in all early adopters (meaning all current and future paid customers, up until this change) allowing them to keep their existing subscription price as long as they don’t cancel it."
It mentions on the blog post that they'll grandfather in existing customers.