Apple iphone 6 updating from version iOS 10.3.2

Hi all

I have an old iPhone 6 that has software version iOS 10.3.2 on it.

Yea, I'm hopeless, I've never let it update as I did once & had problems with it.

Moving forward & in a new job I really need a phone to do a few more things, it won't even sinc with a new email address due to being out of date, I can't even do the QR codes.

The phone is working well in all other respects & I just can't justify starting a new contract or purchasing a new one outright.

What will happen if I allow it to upgrade. I've heard it will crash & be useless.

I'm not a techno savvy person at all so appreciate any advise.

Cheers