Ant Ling's billing upgrade notice sets the end of the daily 500K-token free allowance: 2026-10-31 23:59:59 (Beijing time), after which free credits become a ¥10 voucher issued on the 1st of each month (accounts that upgrade early get a one-off ¥20 voucher, valid 60 days); the official API still answered 200 on 2026-10-16 (usage 36/30/66 tokens, no cost field in the response) → end date Oct 31