Doctor Who Magazine Issue 500 (in-universe)

Peter Capaldi was asked in 2016 by Doctor Who Magazine to write a letter for their 500th issue. Capaldi also recollected that he had been previously asked by Doctor Who Magazine to write a letter for either the one-thousandth or one hundred-thousandth issue, but the actor couldn't remember which. By the 500th issue, there was a comic strip within the magazine. (PROSE: A Letter from the Doctor)