1-14_to_1-17.zip 〈FRESH〉

: 1.17 introduced the foundation for the "Caves & Cliffs" update. While the height limit didn't fully expand until 1.18, 1.17 added many blocks (Copper, Deepslate, Axolotls) that won't exist in your 1.14 chunks.

Is this a you downloaded, or a backup of your own server? 1-14_to_1-17.zip

: Your 1.14 Nether is likely a barren wasteland. Upgrading to 1.17 transforms the Nether into a vibrant dimension with biomes like Crimson Forests and Basalt Deltas. 1.17 added many blocks (Copper