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 1,000th or 100,000th 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)

The Twelfth Doctor mentioned the issue's impending release in his letter for DWM's sister magazine, Doctor Who Adventures. (PROSE: Dear Readers)

Doctor Woah!
The Twelfth Doctor once showed Clara Oswald a copy of DWM 500, which he claimed was the final magazine published on Earth before Facebook became sentient and decimated the population. (NOTVALID: Doctor Whoah!)