NanaZip Drops Simultaneous Stable (6.5.1800.0) and Preview (7.0.1800.0) Builds
Kenji Mouri, the principal developer of NanaZip, published two releases on August 6, 2026: the latest stable build and a preview candidate for the next major version line. Both carry identical upstream base code, with the 7.0 Preview incorporating all fixes from 6.5.1800.0.
NanaZip is an open-source file archiver forked from 7-Zip, designed for modern Windows. It has grown to roughly 15,000 GitHub stars and 384 forks since its creation on August 31, 2021. The project distributes two flavors: NanaZip (Modern) as an MSIX package with XAML-based GUI, and NanaZip Classic as a portable Win32 build targeting Server Core and Windows PE.
The 6.5.1800.0 release marks the first "Update" revision of the 6.5 stable line after it established itself on June 16. The version numbering scheme has been adjusted to eliminate the previous pattern of excessive intermediates. The 6.0 series saw eight update revisions.
"This release includes all the improvements from NanaZip 6.5 Update (6.5.1800.0)," the changelog states for the 7.0 Preview.
Security fixes and versioning reform
The update builds on earlier security remediation. It addresses CVE-2026-58052 (published by Bikini) and continues work from the June 8 release that fixed 13+ issues reported by JarLob. The adjusted release tag timeline now runs Preview → Final → No Tag, with Update and Update Final as intermediates.
The build number follows days since NanaZip's creation date, and the revision tracks releases on that day. Mouri noted the previous pattern "looks more like a baka" when describing the cascade of versions in the 6.0 series.
Community engagement on the 7.0 Preview is modest. Reactions include two thumbs-up and one heart, with notable contributors like linuxman6 and wu858430049 participating in the discussion.
Roadmap and cadence
Both releases reference Issue #913, "NanaZip Technical Focus," opened May 24, 2026. It serves as a public roadmap alignment document with six key priorities: upstream synchronization with 7-Zip mainline, architecture refactoring, supporting infrastructure called Mile.Project, testing improvement, selected read-only format support, and long-term research on K7FS (NanaZip K7 File System).
Mouri explicitly states NanaZip is not his full-time job. He commits to maintaining roughly one major stable version per year when sustainable, balanced against his day job and personal responsibilities.
UI/UX design, security research, and fuzzing are delegated to the community. These areas "may move forward when there are concrete, reviewable, and maintainable contributions," Mouri writes.
It's a rather focused scope for an archiver, though the security remediation and clean versioning do help. The K7FS research topic is explicitly noted as "not a short-term commitment."
What's next
Expect continued synchronization with 7-Zip beyond version 26.02, ongoing architecture refactoring in the 7.0 Preview line, and further read-only format support for ROMFS and littlefs. Mouri's Technical Focus issue suggests K7FS artifacts may mature over time.
Keep in mind that the 6.5 stable line remains the recommended path for most users. The 7.0 Preview is intended for testing and feedback.
Head here to download NanaZip 6.5 Update (6.5.1800.0) from GitHub. The 7.0 Preview (7.0.1800.0) is available separately with the NanaZipPreview_* naming convention.
