Hi @xiaomeng.zhang ,

I would look into the user in question and see what Device they were on as it might just be the set up of the device, that it reports the Device ID capitalized. There wouldn’t be anything that could be done if the SDK is automatically reporting this. What SDK are you using? Can you give me the link of the user in question? One that is in lowercase and the one in uppercase? Thank you!

Kind Regards,
Denis

Hi, Denis, thank you for your reply！

we use segment SDK, and it is for mobile.

But we did not set the device_id，I think this device_id may be generated by amplitude.

And follow is the user link:

https://analytics.amplitude.com/carsome/project/349999/search/16BA29A1-528A-4E67-947C-4EC3E5E46BCA

https://analytics.amplitude.com/carsome/project/349999/search/c6adc3fd07f5e282

Is this the link you want？

@Denis Holmes 

hi, Denis, Looking forward to your reply

Hi @xiaomeng.zhang,

Apologies. I was OOO yesterday. Yes, so looking at the users in question and focusing on the capitalized Device IDs, it would seem the capitalized ones are being sent by Segment themselves and for the iOS users. So it would seem that segment sends the Device ID for iOS users as capitalized. Have you reached out to them to see if they can send it in lower case instead? Otherwise, it will automatically send them as capitalized for all iOS users.

I hope this helps!