Only the open source AndroidAPS for Android and Loop for iOS do this. And then you have a very limited set of pumps you can use.
The Tandem t slim x2 only has support for hypo prevention today, but it supports at home firmware/software updates and they are pretty far along with the FDA on getting approvals for their auto dosing for highs. They anticipate a release this summer.
I wish that OmniPod was further along on this front. I would love to have a tubeless solution and the convenience of not needing to disconnect every time I'm going to get in the water, but the trade-off just isn't worth it IMHO.
https://androidaps.readthedocs.io/en/latest/EN/Getting-Start...
I would be seriously interested in a closed loop Omnipod, but it will be awhile before Iām eligible for a new pump under insurance.
The temporary reduction or even suspension of insulin depending on my activity are key in preventing lows for me.
The closed loop pumps are the biggest improvement I've seen for living with T1. There's always lots of promises, but this is one of the few things that really improves my life on a day to day basis and it just keeps getting better.