We are currently experiencing an unexpected issue with the DeviceCheck query_two_bits endpoint. According to the official documentation (Accessing and Modifying Per-Device Data), the last_update_time field should represent the month and year when the bits were last modified.
The Issue:
For several specific device tokens, our server is receiving a last_update_time value that is set in the future.
Current Date: April 2026
Returned last_update_time: 2026-12 (December 2026)
Here is a response:
{
"body": "{\"bit0\":false,\"bit1\":true,\"last_update_time\":\"2026-12\"}",
"headers": {
"Server": ["Apple"],
"Date": ["Thu, 02 Apr 2026 06:05:23 GMT"],
"Content-Type": ["application/json; charset=UTF-8"],
"Transfer-Encoding": ["chunked"],
"Connection": ["keep-alive"],
"X-Apple-Request-UUID": ["53e16c38-d9f7-4d58-a354-ce07a4eaa35b"],
"X-Responding-Instance": ["af-bit-store-56b5b6b478-k8hnh"],
"Strict-Transport-Security": ["max-age=31536000; includeSubdomains"],
"X-Frame-Options": ["SAMEORIGIN"],
"X-Content-Type-Options": ["nosniff"],
"X-XSS-Protection": ["1; mode=block"]
},
"statusCode": "OK",
"statusCodeValue": 200
}
Technical Details:
Endpoint: https://api.development.devicecheck.apple.com/v1/query_two_bits (also occurring in Production)
Response Body Example:
JSON
{
"bit0": true,
"bit1": false,
"last_update_time": "2026-12"
}
Observations: This occurs even when our server has not sent an update_two_bits request for that specific device in the current month.
Questions:
Is there a known issue with the timestamp synchronization or regional database propagation for DeviceCheck?
Does the last_update_time field ever represent an expiration date or any value other than the "last modified" month?
Best regards,
