So my friend got this email from OneSignal
Due to a change that may occur as part of the upcoming iOS 13 release, you must update to the latest versio
You may use this method to fetch the device token on iOS 13 onwards:
Objective-C:
+ (NSString *)stringFromDeviceToken:(NSData *)deviceToken {
NSUInteger length = deviceToken.length;
if (length == 0) {
return nil;
}
const unsigned char *buffer = deviceToken.bytes;
NSMutableString *hexString = [NSMutableString stringWithCapacity:(length * 2)];
for (int i = 0; i < length; ++i) {
[hexString appendFormat:@"%02x", buffer[i]];
}
return [hexString copy];
}
Swift 5.0 (Untested)
class func string(fromDeviceToken deviceToken: Data?) -> String? {
let length = deviceToken?.count ?? 0
if length == 0 {
return nil
}
let buffer = UInt8(deviceToken?.bytes ?? 0)
var hexString = String(repeating: "\0", count: length * 2)
for i in 0..<length {
hexString += String(format: "%02x", buffer[i])
}
return hexString
}
Taken from OneSignal blog