Honda didn’t carry over anything except the name in 2018. Your 2015 for the most part is the original design platform that was first released in 2001. Minor plastic changes, stereo up grades, transmission parts changes between 2001 and 2017. The fact that your 2015 engine has sleeved piston cylinders and the 2018+ has a coated over aluminum block cylinders, the only similarity is that they both have 6 cylinders.