Hi lovespiri,
This happens because 8.7 is exclusively an online update. The most recent retails/OEMs are officially 8.5 builds - but as soon as you purchase the box, install BullGuard and update it, it will upgrade to 8.7. You can also use a 8.5 license key on an 8.7 (if you already have it installed).
Also note that even though the website states you're downloading 8.5, the kit is actually an 8.7 one.
If you have further questions, please do not hesitate to ask.