I haven't played a game of league since 2012 when they added extra stuff to Twisted Treeline games

So... What all has changed in League gameplay since then? Last time I played was right when they had just added an extra element to Twisted Treeline gameplay. i cant remember exactly what it was i think it was new turrets or something like that, and I remember that I played a few games of TT blatantly ignoring whatever it was that they added and was tired of having a hard time learning how to play all over again and that was when i quit playing. Obviously a lot more than that has changed since I last played almost 7 years ago, and I was wondering if anyone else in the community remembers when TT was changed, and can explain to me exactly what it was that changed so that i might be able to figure out what I was doing wrong on the" 2012 new" TT and what's changed since then as well? I'm a little intimidated to just hop back into League because I've heard about a lot of changes since I quit playing and I'd like to know what to expect to be different before I play for the first time in 7 years. lol