Originally Posted By: chaosmagnet
My offline maps app (MotionX GPS) is still working on my device but does not appear to be available in the App Store any more. I’ll work on finding one that’s current.

Thanks! MotionX GPS is the offline map app I use, but some things had stopped working.

I found the official discontinuation announcement on the company site here: https://support.motionx.com/#

Let us know if you find an offline map app you like. For offline access, I see membership fees for both GAIA GPS ($17/yr) and Alltrails ($20/yr for 3-year).

There's a recent list of offline map apps here, but at first blush they don't seem very wilderness friendly:
Offline map apps for IOS and Android, Jan 2021

This 2018 listing of offline map apps for hiking looks like a better bet (and lists MotionX GPS ... sigh)
Offline Hiking map apps: IOS and Android 2018
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A signal mirror should backup a radio distress signal, like a 406 MHz PLB (ACR PLB) (Ocean Signal PLB)