I want to connect 50 ESP8266 in AP-Mode

Here’s the code in WiFiAP.h that has to be modified:

class WiFiAPClass
{

// ----------------------------------------------------------------------------------------------
// ----------------------------------------- AP function ----------------------------------------
// ----------------------------------------------------------------------------------------------

public:

bool softAP(const char* ssid, const char* passphrase = NULL, int channel = 1, int ssid_hidden = 0, int max_connection = 4);

Change max_connection to something else.