According to TechFlow, Claude announced on June 13 that it will suspend access to the Fable 5 model for all users because of a related U.S. government ban. Under the notice, new sessions will no longer continue on Fable 5. Instead, they will switch to the default model set by the user, or to Opus 4.8 if that setting applies.
Existing sessions and platform API calls will fail
Claude also stated that Fable 5 sessions that are already open will return an error and terminate directly. Users who were running conversations on Fable 5 will need to restart their work on another available Claude model rather than continue under the suspended model.
The same change applies to Claude Platform. API requests made to Fable 5 will also return errors, according to the announcement. Developers are being told to move related applications and integrations to other Claude models as soon as possible, so services that depend on Fable 5 do not break during model calls.