Transfer your license to a new phone.
License Bought with Google Play
License Bought with Taobao
License Bought with PayPal
License Bought with Avangate
Transfer by Old Register Code
No need to transfer the license in following cases (because the MachineID of the phone can not be changed):
Transfer the license only when you change your phone, for example change it from HTC M9 to Galaxy S7, or change it from a Nexus 6 to another Nexus 6.