The top four flights of the English football league system consist of the Premier League and three lower divisions. Chelsea is reading a newspaper from July of a year from 1993 to 2019.
Chelsea: "I will give you the position of a team in each league and you tell me the year the newspaper was printed."
Derby: "Does the table show the results at the end of the previous season, or the start of the next one?"
Chelsea: "I won't tell you that, but the bottom team in each league was respectively W, X, Y, and Z."
Derby: "I can't say for sure."
Chelsea: "I am in the Premier League top six."
Derby: "Ah, I know now."
What season was it, and what year was the newspaper printed?
Bonus questions on this season:
What's special about the bottom team overall. Why does this not apply to the top team overall?