# Unknown Token Canister Query Strategies

**URL:** <https://forum.dfinity.org/t/unknown-token-canister-query-strategies/34543>\
**Category:** Language Support\
**Created:** [August 28, 2024, 8:08pm UTC](https://forum.dfinity.org/t/unknown-token-canister-query-strategies/34543 "2024-08-28T20:08:43Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![skilesare](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/skilesare/32/5609_2.png) [@skilesare](https://forum.dfinity.org/u/skilesare)\
**Post date:** [August 28, 2024, 9:01pm UTC](https://forum.dfinity.org/t/unknown-token-canister-query-strategies/34543/4 "2024-08-28T21:01:48Z")

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> [@evanmcfarland](#):
>
> then have autonomous checks that remove from the list if the metadata endpoints return something undesirable.

Here in is the problem…those autonomous checks to a canister that you don’t control gives that canister the ability to block your upgrade. See this post: [Can you upgrade a canister without stopping it? Yes, eh, no, eh … maybe](https://forum.dfinity.org/t/can-you-upgrade-a-canister-without-stopping-it-yes-eh-no-eh-maybe/3962)

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