There are a whole lot of small changes coming to League of Legends with the release of Patch 6.17 — most aimed at slightly tweaking over- or underperforming champions.
But one change will significantly alter the way you play the game, especially around turrets.
There are two changes coming to turrets in 6.17, and both of them are important. In League, turrets prioritize minions when choosing who to attack, only attacking champions if 1) there are no minions in range OR 2) if the enemy champion is attacking an allied champion.
Previously, scenario 2 would only trigger if both champions (the one attacking and the one being attacked) were within range of the tower. Now, if you are within range of an enemy tower and are attacking an enemy champion that is not in range of the tower, you will still be attacked by the turret.
Here’s a handy visual example from Riot’s announcement of the upcoming changes. With the old turret AI, Varus would not be targeted by the turret here for attacking Singed. With the new turret AI, he is.
The other change to turret AI is just as important to know. Previously, if multiple enemy champions were in range of a turret when the final non-champion target died (i.e., the last minion in a wave), the turret would switch targets to a random champion in its range. Now, turrets will prioritize the closest champion, making these scenarios much more predictable
So tl;dr — if you attack an enemy champion while you are in range of a tower, you’re getting hit, and tower champion aggro will prioritize champions closest to it.