New to DnD. Accidentally bought wrong books.

Hello all. I recently got into DnD with a local group, and have been trying to move my goblin gloomstalker ranger to the app to make sure that all the math is mathing while I learn everything myself. After looking it up, I'd found that the goblin race was included in the "Mordenkainen Presents: Monsters of the Multiverse" book, and the gloomstalker subclass was included in the "Xanathar's Guide to Everything" book. So, I purchased both books, but apparently there was some version discrepancy I wasn't aware of, or something to that effect, because I can't choose that subclass for a level 6 goblin. I was wondering if there was any way to exchange whichever book is causing the issue, with the appropriate version, or anything like that?

Quote from wagnarokkr >>

 Or, if you want to use the updated 2024 version of the Ranger class and the Gloom Stalker subclass, you can purchase the 2024 Player's Handbook.

 You should really check with your group which version of the classes they're playing with before buying more books. If they're still on the old rules, and they might well be, then you're fine for now.

Ah. I didn't know that the different classes were separated by version. Thank you. ^^ That answered the question.