Can't update my nokia lumia 521 to wp 8.1

[hasper8]

please i just got nokia lumia 521 and am trying to update it to wp 8.1 but i am been told to use the developers preview app if i have registered add an app developer but in trying to do so am been ask to input my credit card details which i dont have, please is there not any other way i can update my 521.

 

[T Moore]

Many 521 phones have been bricked taking them to 10 and finding out the phone has many problems and then trying to get them back to 8