Last checked and updated on 10 Jun 2026
What Is New in NGINX 1.4
NGINX 1.4 introduces a focused set of changes, primarily centered on enhancing the mail proxy module and addressing specific bugs. This release is more about refinement than a major feature overhaul.
| Category | Description |
|---|---|
| New Feature | Added the proxy_pass_error_message directive for mail proxy. |
| Bug Fixes | Resolved issues with the mail proxy module and SSL handshakes. |
What mail proxy improvements were made?
The main addition is the proxy_pass_error_message directive. This gives you more control over error handling between the client and the upstream authentication server in your mail proxy setup.
Before this, you had less flexibility in managing how authentication errors were communicated. This directive lets you fine-tune that behavior, which is crucial for building robust mail routing systems.
Were there any SSL-related fixes?
Yes, a bug was fixed where a worker process could terminate unexpectedly during an SSL handshake. This was a potential stability issue, especially under heavy load with many new SSL connections being established.
In practice, this fix made the core HTTP handling more resilient. It prevents a specific crash scenario that could have taken down a connection thread.
FAQ
What is the single most important change in NGINX 1.4?
The introduction of the proxy_pass_error_message directive for the mail module. It's a key improvement for anyone using NGINX as a mail proxy, as it provides better error handling between the client and the auth server.
Does NGINX 1.4 add any new HTTP modules or core features?
No, this release is quite focused. The notable change is specific to the mail proxy module. The rest of the release consists of bug fixes to improve stability.
I don't use the mail module. Should I still upgrade?
Probably for the SSL handshake bug fix alone. If your servers handle a high volume of SSL/TLS connections, the patch that prevents a worker crash during a handshake adds valuable stability.
Is the proxy_pass_error_message directive used in the http or stream block?
Neither. It's a directive specific to the mail proxy module, so you configure it within the mail {} block in your nginx.conf configuration file.
Where can I read the official changes for this version?
The complete and official changelog is maintained on the nginx.org website. Always refer to it for the authoritative list of changes, bug fixes, and new directives. (nginx.org/en/CHANGES)