I am extremely sceptical about this.

Some very clever people have been trying for a lot of years to prove or disprove the paranormal with the aid of electronics.

And now a bunch of programmers have cracked it on a standard piece of every day phone kit? Hmmm.

I'm a programmer. Its been my paid job for 20 years, and my hobby for 30 years. I think I'm pretty good at it. Yet I can't achieve anything like this, simply because I know that the hardware has nothing in it that would facilitate this. The phone itself will have a number of sensors. A mic and camera, motion sensor, accelerometer, and sometimes a few others depending on the phone but nothing special. The CPU in the phone will be a fairly run of the mill CPU, probably with some limited digital signal processing capability built in. And the code that runs on the phone will boil down to plain old cold logic.

If these apps worked, it would be the mainstream news event of a lifetime. It would be bigger than confirmation of multiple dimensions and alien life put together. A spirit communicating through something as tangible, predictable, repeatable and logical as an mass produced mainstream electronic device.

Of course what IS possible on the hardware of a common low cost mobile phone, is a bit of speech recognition, a bit of speech synthesis, some very limited artificial intelligence, some spooky digital audio effects, and some code to tie it all together that follows the similar logic to the standard charlatan, saying vague things that statistically are likely to mean something to the end user, and responding to their reactions. Add in the fact that most people grant access to these apps without even checking what they're granting access to, and you've suddenly got their facebook friend list and all their timeline, their browsing habits, the names of all their contacts etc, and suddenly you've got a pretty clever piece of code that might convince the average school kid that they're talking to great auntie Mable. All while the app is profiling you and raising revenue for its producers by targeting ads at you or selling profile data to a list broker. Sorry, just my opinion. It is always possible that I might be wrong.