Update a minecraft server version. Always deletes old "server.jar".

update.py

import os
import json
from subprocess import run

try:
    import wget
except ImportError:
    run(["pip", "install", "wget", "--upgrade"])


if os.path.isfile("version_manifest.json"):
    os.remove("version_manifest.json")
    wget.download("https://launchermeta.mojang.com/mc/game/version_manifest.json")

with open("version_manifest.json") as a:
    j = json.load(a)
v = j["latest"]["release"]

for i in range(len(j["versions"])):
    if j["versions"][i]["id"] == v:
        link = j["versions"][i]["url"]

version = v + ".json"

if os.path.isfile(version):
    os.remove(version)
wget.download(link)

with open(version) as l:
    server_json = json.load(l)

url = server_json["downloads"]["server"]["url"]

if os.path.isfile("server.jar"):
    os.remove("server.jar")

wget.download(url)

os.remove(version)
os.remove("version_manifest.json")