OS is Windows 10. This is the compilation error I get:
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Arduino: 1.0.6 (Windows NT (unknown)), Board: "Arduino Mega 2560 or Mega ADK"
C:\Program Files (x86)\Arduino\libraries\GSM\GSM3ShieldV1ModemVerification.cpp: In member function 'String GSM3ShieldV1ModemVerification::getIMEI()':
C:\Program Files (x86)\Arduino\libraries\GSM\GSM3ShieldV1ModemVerification.cpp:72: error: conversion from 'int' to 'String' is ambiguous
C:\Program Files (x86)\Arduino\hardware\arduino\cores\arduino/WString.h:61: note: candidates are: String::String(const __FlashStringHelper*)
C:\Program Files (x86)\Arduino\hardware\arduino\cores\arduino/WString.h:59: note: String::String(const char*)