Starting Thursday, June 28 2023, Salesforce will no longer support the use of UUID token formats for API Clients in Commerce Cloud Account Manager. New API clients now only support the JWT access token format.
How: When an organization has one or more API clients using the UUID access token, a notification banner is displayed in Account Manager. Salesforce recommends that customers update their Access Token Format settings for existing API clients from UUID tokens to JWT tokens. See Time to switch JWT.
API Clients that continue to use the UUID access token format will be automatically switched to JWT token format. Salesforce will time token switching using a staggered approach. An API client can be switched to the JWT token format at any time during the process. When an API client is switched to JWT, Account Manager contact users are notified by email.