http2 regression

About this tag
The http2 regression tag covers issues where Windows updates, particularly KB5066835 for Windows 11, break local IIS-hosted sites and developer workflows by causing ERR_CONNECTION_RESET, ERR_HTTP2_PROTOCOL_ERROR, and failures of localhost-based services. Discussions focus on mitigations and rollback guides for affected developers, sysadmins, and commercial applications. Practical workarounds are available but each carries trade-offs. This tag is relevant for those troubleshooting HTTP/2 protocol errors after applying recent Windows cumulative updates.

  1. KB5066835 Breaks Local IIS on Windows 11: Mitigations and Rollback Guide

    A wide-ranging October 2025 cumulative update for Windows 11 (KB5066835), and at least one related preview package, has broken many local IIS-hosted sites and developer workflows — causing ERR_CONNECTION_RESET, ERR_HTTP2_PROTOCOL_ERROR and outright failure of localhost-based services for...
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    • http.sys http2 http2 regression iis iis express kb5066835 local iis localhost localhost debugging patch management patch tuesday 2025 regression rollback windows 11
    • Replies: 9
    • Forum: Windows News