Differences between player's handbook 5e and 5.5e

Hi! Beginner player here. I'm making my first character right now, and just picked up the player's handbook from my local library to help with that. Problem is: I had not realised it was the older, 2014 one (though printed in 2018). The oneshot we'll be playing this week will be 5.5e, and in the case we do continue the campaign after that will probably be 5.5e too.

So now I'm wondering, how much of a difference is there? Is it any use reading it at all or am i better of using dndbeyond pages only - or is it best to look at both?

For reference, i think i will be playing a gnome rogue. I might still change the race, and possibly also class, but that would be to either bard or ranger (unless i can somehow make another class like monk or fighter fit the rogue type role in the party).

Also I have played two brief oneshots with other beginners before, so I'n not at a total zero of knowledge, but i still know relatively little. I'm planning to create my character sheet in dndbeyond (but with the option that makes you pick everything yourself)

Are there any specific differences i should watch out for if i do use the player's handbook?

Thanks for any help!