7 years difference from now is really a nice term to hodl. I'm sure by then, we are going to see cryptocurrency climbing and officially recognized and used as financial payment system.

However, my advise is to be sure you secure your passwords.

For your curiosity about upgrade of bitcoin if it happens , I think it won't get to losing of coins. Upgrades are usually made to make an app or facility work better by adding new technology and accommodating the existing one. Just for instance, coinomi just did upgrade, freewallet too and existing coins were not lost.

You just would follow a prescribed direction and all will be cool. Good luck.