Yes, sorry, I thought the terrain generation wouldn't change, but it has changed a bit. There are a lot more oceans now, apparently, or so it seems when I compare it to the old map from 1.8+, but some of the areas look mostly the same as before.
If you want it, I can probably attach some more of the 1.8 terrain to your border. Otherwise I can help making it look natural.
But no, the map will absolutely not be restarted. We didn't spend 8 months on this just to start over.