DeepLLegitimate endpoint no longer working after authentication method deprecation

[Chozothebrozo]

Greetings,
DeepL published recently that as of 1/15 they were deprecating support for various API authentication methods and would now require a header containing the API key. Copy/pasted the email notification below this post

Plugin throws 403 forbidden errors as expected due to the change and attempts to hit the fallback endpoints for translation, but eventually fully fails due to hitting the failure limits.

Any chance an update to the API request construction would be available or should users fully switch to a different endpoint at this time? (I personally really liked DeepLLegit)

DeepL email below ----
We're writing to inform you that our team is here to support your migration of an important upcoming change to the DeepL API. We’ve extended the deadline from the originally scheduled date of November 1, 2025 to ensure you have sufficient time to complete any necessary updates. If you do not take action, your DeepL integration will no longer work after January 15, 2026.

What’s changing:

Effective January 15, 2026, DeepL will discontinue support for the following legacy authentication methods:

auth_key in query parameters
auth_key in form body data
auth_key in JSON body data
After this date, all API requests must use the standard Authorization header for authentication.

What you need to do:
Update your DeepL API integration to authenticate using the Authorization header:
Authorization: DeepL-Auth-Key YOUR_API_KEY

Full migration instructions and code examples are available in our documentation.

If your application continues to use legacy methods after this date, requests will fail with a 403 Forbidden error.