Users configured with explicit old-format Opus model IDs (claude-opus-4-20250514, claude-opus-4-1-20250805, claude-opus-4-0, claude-opus-4-1) are automatically migrated to the canonical opus alias. A notification "Model updated to Opus 4.6" is shown briefly after the migration.
Details
Applies to first-party users only
A new allowlist (fXz) defines the four legacy Opus model strings subject to migration
The previous Opus 4.5 → Pro migration notification ("Model updated to Opus 4.5") has been replaced by this updated path
