OLD wallets dont sync with current network. You must always upgrade to the latest wallet. OR just use an Android wallet that auto-updates like Zelcore wallet then you have to do nothing. Windows wallets are full nodes, they help the network and you are in full control and the actual hard work and network blockchain is saved and updated on your PC. Android wallets are usually light nodes, you are still in control of your private keys but all the hardwork is done remotely on a server that you just connect to and dont have to download the full chain.

Meanwhile your coins are safe BUT if you delete your %appdata% folder or specifically wallet.dat, you could lose your coins during your upgrade.

Just keep in mind that Android wallets while convenient could be insecure just like Android itself is a big mess, every app can read all your data or it wont work if you don't give it permission. Want to know why stupid apps like Candy Crush need to be able to read every single file on your phone and your SD card, all your photos, etc? Now you know. And Google doesn't care. On iPhone, apps are limited to read and write in their own folder only. Also, an Android app developer could update their app to send himself all your coins, not that I am saying they would but it could be their exit scam or honest hack of their code. If you have it set to autoupdate, which most of us do, it could mean a very non-secure way to store your life savings.