The latest version should be able to open an old version of wallet.dat, you don't need to download old Bitcoin Core versions.
For the balance, if the wallet was used before, there should be at least some unverified transactions in the transactions tab (your previous transactions);
if it's totally clear, it may be an unused wallet or had the wallet transactions zapped before they get verified.

To get the correct balance, your node need to be synced to the point (time) when your wallet transactions were received, that will require you to download and verify hundreds of gigabytes equals to a few days of waiting depending your machine and internet speed.

Lastly, if it's not an "HD" wallet (displayed below the GUI), and it's an old backup, it may be missing the keys for the transactions after that backup copy.
You need to find the latest backup copy in that case.