Cognito Generating UUID V7 instead of UUID V4

Question

Cognito Generating for new users, UUID V7 instead of UUID V4, that is supposed to be default.
I could not find where to change it in order to generate as UUID V4.

Answer

Cognito is responsible for generating an arbitrary unique string for the `sub` for its user pool.  You can't control (or make assumptions) about the format.  From https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-settings-attributes.html#cognito-user-pools-standard-attributes

> **sub**
>
> The `sub` attribute is a unique user identifier within each user pool.

See also https://repost.aws/questions/QUfWN5qGq8R5WsocQaP1A9Dg/cognito-sub-attribute-seems-to-be-no-more-a-valid-uuid

Cognito Generating UUID V7 instead of UUID V4

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