21 October, GMT +0, 15:45 - A succesful ping has been made! The devs did it.
This means they succesfully reverse engineered the neccesary parts of Niantics code. Now there is not an API yet, but FPM will 100% come back. Probably within 48 hours. For everyones scanners to come back they would have to build a public API and release it. Their first ping was probably made with a lot of manual guidance, automating the process (building the API) won't take terribly long. Last time it took them 9 hours or so, it might be longer this time (less devs should hurt this part especially).
The API uses Niantics isolated hashing function. It has not been reverse engineered, but they isolated the part that does the code. This is legally "stealing" code from Niantic and distribution (if they want to share their API fix) will be harder. Hosting this code is C&D worthy if I am correct. This is in the end a losing war for Niantic though, last time they C&Ded someones map it had a couple of thousand downloads..
For now.. They did the hard part, what is left is easy stuff, Hooray!
21 October, GMT +0, 16:00 - Heard that the devs do intend on releasing a public API, still not 100% confirmed, but I'd put my money on it.
22 October, GMT +0, 00:00 - Today was a great day, the API is coming.
With the API done, I am not done writing.. yet.
Legal issues
The solution of the devs isn't the cleanest one, Niantic will have a strong copyright position against anyone directly using the API. IE: host your map. FPM users will be safe. I am not sure how FPM intends to go about this.
Why was the previous API solution "legal" and this one "illegal"?
Niantic has made pokemon go and within that there is the part that contructs "unknown6". In the end constructing unknown6 is just a series of computations of 1's and 0's, math. You can not patent 2+2, neither can Niantic patent the way in which unknown6 is made. With the first API-***** the devs made their own Unknown6. The reverse engineered the math behind 2+2 (unknown6) and made an application which did 2+2.
Now what you can patent is the way in which you write 2+2, to further my example: the font. In terms of code these are comments/white space/variable names/ etc. During the first API break they wrote their own 2+2, but now it is slightly different.
The devs had trouble reverse engineering the hashing function. Therefore they just "stole" the hashing function from Niantic. They isolated the part that does the hashing function and copy-pasted it into their solution. This means they also are using the "font" that Niantic uses, which makes the solution prone to copyright claims.
22 October 2016, GMT +0, 02:30 - The devs think the legal issue is too big to pass on, If I understand correctly they will attempt to reverse the hashingfunction after all. They will only release the API after that, (another 99% confirmation that the API will indeed be public).
The long wait continues. reengineering effort continues.