Minecraft - Old World changed completely by 1.14 instead of city now new biotope?

My old minecraft world where I had built a city was completely changed by the new update! My city is gone at the moment is now jungle! What do I do now? How can I get back to my old city?

That's because the 1.13 world, or whatever version you've built the city, is not compatible with the 1.14. If you open the world about the 1.13 … In the version where you created it, your city should still be there or the world… Just try it…