Worked on stabilizing multisite routing in the discourse/discourse_docker repository by addressing issues with Nginx Host header handling. Implemented a targeted fix using YAML and DevOps practices to ensure the original Host header was preserved in upstream Nginx blocks, which is essential for accurate multisite routing. After deploying the patch, identified compatibility issues with newer Nginx versions and reverted the change to maintain system stability. Documented the rationale behind the revert and provided guidance for future compatibility checks, balancing routing fidelity with the support matrix. The work demonstrated careful attention to backward compatibility and robust documentation for ongoing maintenance.