Nginx 1.31.4

nginx 1.31.4 was released on August 19, 2026, bringing one notable feature, a behavioral change affecting HTTP/2 and gRPC upstreams, and a fresh round of bug fixes across several modules.

Feature: PROXY Protocol v2 Support

The proxy_protocol directive in the stream and mail modules now supports PROXY protocol version 2. This allows stream and mail configurations to pass client connection metadata using the binary version 2 framing, alongside the existing version 1 text format.

Behavior Change for Backend Requests

HTTP/2 and gRPC requests to backends are now always sent with the :authority pseudo-header, while HTTP/1.1 requests are always sent with the Host header. This normalization makes upstream routing behavior more consistent and predictable across protocol versions.

Bug Fixes

• Fixed a segmentation fault that could occur in a worker process when the select method was used.
• Incomplete gRPC responses with a non-zero Content-Length header are now treated as malformed rather than silently consumed.
• Restored binary compatibility with third-party modules using script codes — a regression that had appeared in 1.31.3.
• Fixed a bug in the ngx_http_perl_module (thanks to David Carlier).
• Additional bug fixes in HTTP/2, HTTP/3, the ngx_http_image_filter_module, and the ngx_http_grpc_module.

Upgrade Notes

No security advisories accompany this release, making it a routine maintenance update. Operators running nginx 1.31.x — particularly those using stream or mail proxies, or HTTP/2 upstreams with third-party modules built against 1.31.3 — should schedule the upgrade. As always, review your configuration for any reliance on the previous Host/:authority behavior before rolling out.