this is awesome
"So, if you’ve just bought a codex for a new army, or the rules for Warhammer 40,000 itself, in the weeks before the new edition was announced last Saturday, we’ll send you a voucher for the cost of your book. Usually, we’d do this for up to 4 weeks before the update was announced, but as we’re so excited about the new edition of Warhammer 40,000, we’ll be extending this to 8 weeks (8 weeks for the 8th edition!). And of course, you can keep your book(s).
You can claim a voucher no matter where you bought your codex and/or rulebook, as long as you have your proof of purchase and it’s dated between the 25th of February 2017 and the 22nd of April 2017."