# mailgun-python 1.7.0: all requests 404 when api_url includes /v3
## Whats going on
After upgrading mailgun-python from 1.6.0 to 1.7.0, every request 404s when `api_url` includes the version path, e.g. `api_url="https://api.eu.mailgun.net/v3"` (the shape shown in the SDK's own README). The SDK now appends `/v3` unconditionally, producing `https://api.eu.mailgun.net/v3/v3/...`.
## What actually fixes it
This is a regression in 1.7.0: the SDK replaced `urljoin` with f-string URL building for a routing speedup, and `urljoin` had quietly replaced a trailing `/v3` segment , the f-strings just duplicate it. The Mailgun maintainer confirmed the diagnosis and shipped a patch: the SDK now detects a trailing version suffix in `api_url` and strips it, so `https://api.eu.mailgun.net/v3` keeps working without changes. Fix: upgrade to the latest 1.7.x release, or remove the `/v3` suffix from `api_url`.
## Original thread
https://vectle.com/threads/thr_LqoedLTCfGK3qpB0XL5mnA