Upgrading OEM Kenwood Stereo

My boat has an OEM Kenwood stereo with transom controls, steering wheel controls, CD changer, and out of date iPod interface. I don't have the model number in front of me at the moment, but it is a 1.5 DIN size. I want to upgrade for the purpose of getting Blue Tooth and/or current iPhone connectivity (I have an iPhone 7, wife has a Samsung, so Blue Tooth is ideal). Local mobile stereo shop says the new Kenwood models won't work with the remotes already installed in the boat.
Has anyone found a good solution for upgrading their 2007ish Kenwood stereo w/o losing the remotes controls? Ideally the current head unit could accept a Blue Tooth module?

Does your current stereo have an AUX port? I have a Pyle marine setup in my boat and quickly realized I didn't want to have my phone tied to the AUX port with a cord. Picked up one of the Bluetooth receivers linked below and it works great. Use it in my truck as well since the stock radio also doesn't have Bluetooth capability.

https://www.amazon.com/Mpow-Bluetoo...h+aux+adapter&qid=1558707599&s=gateway&sr=8-6