Get the most recent modification timestamp across all boundaries.

Returns the latest updated_at datetime from both ADM0 and ADM1 boundary tables. Useful for cache invalidation and determining if boundary data needs to be refreshed.

Query Parameters:

• release_type: geoBoundaries release type (gbOpen, gbHumanitarian, gbAuthoritative, default: gbOpen)

Returns:

• 200: Last updated timestamp
• 400: Invalid query parameters
• 404: No boundary data found
• 500: Server error

Response Structure: { "data": { "last_updated": "2025-01-26T10:30:00.000000", "release_type": "gbOpen" } }