Fedora 46 approves RPM v6 package format with modernized cryptography and UTF-8 enforcement

The Fedora Engineering and Steering Committee has approved the RPM v6 package format for Fedora 46, scheduled for release by late April 2027. This upgrade from the current RPM v4 format introduces improved cryptographic algorithms, 64-bit size tags, and mandatory UTF-8 string encoding throughout the package metadata. The change represents a structural modernization of Fedora's core packaging infrastructure rather than a user-visible feature addition.

Alongside RPM v6, FESCo approved several companion changes: a new RPM macro for Emacs package installation to standard directories with an associated dependency generator, libchewing 0.14, libvirt's transition to NFTables for network filtering, LMDB 1.0 adoption, and permanent updates policy exceptions for media processing libraries (live555 and openapv) plus Python-OpenAI due to security-critical update velocity. A proposal to enable Thin LTO build flags across Fedora packages was rejected without any FESCo votes in favor.

What changes in RPM v6 for Fedora 46

• Cryptographic modernization: RPM v6 replaces v4's cryptographic mechanisms with improved algorithms, addressing long-term security posture of the package format itself.
• 64-bit size tags: The format expands tag sizes to 64-bit, removing limitations that could affect very large packages or metadata structures in v4.
• UTF-8 enforcement: All strings in RPM v6 packages are required to be UTF-8 encoded, eliminating encoding ambiguity and locale-dependent parsing issues present in v4.
• Emacs packaging infrastructure: A dedicated RPM macro will install Emacs packages to their expected directory paths, accompanied by a dependency generator that automatically extracts Emacs-specific package metadata.
• Thin LTO rejection: The proposal to adopt Thin Link-Time Optimization build flags across Fedora packages failed to gain any FESCo support, deferring potential compile-time and binary-size optimizations.

Why it matters

The RPM v6 migration positions Fedora as the first major enterprise-grade distribution to adopt the modernized format, potentially pressuring RHEL, openSUSE, and other RPM-based distributions to follow. For developers and packagers, the UTF-8 mandate and 64-bit tags reduce subtle build and installation failures, while the Emacs infrastructure improvements lower barrier to entry for Lisp package maintainers. The Thin LTO rejection preserves status quo build semantics but leaves performance optimization opportunities on the table for at least another release cycle.