When should we raise versioning for API responses, and when not?

API versioning should be increased when making changes that break backward compatibility (breaking changes). Such changes include:

• Deletion or renaming of existing fields in the response.
• Changing the data type of fields.
• Changing the response structure, which prevents clients from correctly processing the data.

Changes that do not require version increase:

• Adding new optional fields to the response (clients can ignore them).
• Adding new endpoints.
• Fixing bugs that do not affect the structure and format of the response.

Thus, if changes can break existing clients, the API version should be increased.