Content Understanding API version 2024-12-01-preview retired - create_analyzer fails

Description

The ContentUnderstandingDescriber in app/backend/prepdocslib/mediadescriber.py uses CU_API_VERSION = "2024-12-01-preview" (line 30). This API version has been retired by Azure, causing the analyzer creation to fail during deployment:

Exception: ('Error creating analyzer', '{"error":{"code":"Gone","message":"The requested API version has been retired.","innererror":{"code":"ApiVersionRetired","message":"The requested API version has been retired. Please migrate to the latest GA version."}}}')

This breaks the post-deployment setup (prepdocs.py -> ingestion_strategy.setup() -> media_describer.create_analyzer()).

Environment

• Region: North Europe
• Resource type: Azure AI Services (Foundry)
• Date observed: 2026-08-09

Current supported versions

According to the REST API docs, the supported versions are:

• 2024-12-01-preview (listed but retired in some regions)
• 2025-05-01-preview
• 2025-11-01 (latest GA)

Proposed fix

Update CU_API_VERSION in mediadescriber.py line 30:

# Before
CU_API_VERSION = "2024-12-01-preview"

# After
CU_API_VERSION = "2025-05-01-preview"  # or "2025-11-01" if schema is compatible

The analyzer schema (using baseAnalyzerId, scenario, config, fieldSchema) needs to be verified against the newer API version as the request body format may have changed.

Reproduction

Deploy to a region where 2024-12-01-preview has been retired, then run:

azd deploy

The deploy succeeds but the post-deploy knowledge base setup fails.