I have added UDID in upper case in Developer account.Now its not allowing me to change it or to add the same UDID in lower case by clicking +(add new).I want to know whethe
There is no way to do that. Even if you disable the upper case UDID and try to add the lower case one, it simply re-enables the uppercase UDID.
You will need to call apple support and have them remove it, then you need to add it again.
Sorry, Not possible..U cannot modify it once it is registered. U can modify or delete only at the time of renewal of your developer account. Contact Apple Support Team for further assistance..!
Refer Below Link:
https://forums.developer.apple.com/thread/24340
I guess you can use device. You can't edit UDID of device You added once. after account expire You can remove devices which You want to remove and add/edit devices.
A UDID is a hex number. There's no difference between upper case and lower case. You do not need to add or modify the UDID.