Verifying old code suddenly fails?

Troubleshooting
2

Compiler seems to now struggle with certain function prototypes, particularly those that use structs. So, you can try forward declaring the function (as it should be anyway) at the beginning of the .ino (just after the #include directives).

// This #include statement was automatically added by the Particle IDE.
#include "neopixel/neopixel.h"
#include <stdio.h>
#include <string.h>
#include <math.h>

#define PIXEL_COUNT 50

int number_for_key(String key, struct entry dict[]);
// etc ...