What WFC is, and what it isn't
WFC doesn't filter traffic itself. The developer says it does no packet filtering and doesn't block or allow connections. Windows Firewall does that, based on its existing rules. WFC is a faster front end for Windows Firewall. It adds a system-tray interface, notifications for blocked outbound connections, and rule management.
The four filtering profiles are:
- High: blocks all inbound and outbound connections.
- Medium: blocks outbound connections that don't match a rule.
- Low: allows outbound connections that don't match a rule.
- No Filtering: turns Windows Firewall off.
The Neowin listing adds some history. Malwarebytes acquired the product in 2018, and the full edition has been free since then. Neowin lists the 6.39.0.0 download as 3.4 MB freeware. That size and price come from Neowin. The developer's changelog doesn't confirm them.
What's new in 6.39.0.0
The developer's changelog dates this release to November 13, 2026 and lists three additions:
- Dark theme support. The changelog gives no detail on how it's enabled, whether it follows the Windows app mode setting, or which windows it covers. Check the settings after updating.
- Custom focus visual styles. These are meant to improve keyboard navigation. The practical benefit is a clearer view of which control has focus when you tab through the panels.
- Reworked Shell Integration with temporary rules. Shell Integration is the right-click menu entry on executable files. The changelog says only that the rework lets you create temporary rules from it. It doesn't list the menu items or the expiry choices.
Temporary rules in context
Temporary rules aren't new to WFC. Version 6.31.0.0, from April 2026, added the ability to create them from the Connections Log. The latest change brings the same idea to the right-click menu.
The developer's page describes temporary rules as automatically deleted when they expire or on program restart. The user guide says a temporary rule can be set to expire when WFC is restarted, or after 60, 10 or 5 minutes. The guide also says temporary rules show in blue text in Rules Panel. These descriptions come from the product documentation. They aren't restated in the 6.39.0.0 changelog.
A typical use is running an installer or portable tool once. A temporary allow rule means you don't have to remember to delete the permanent rule later.
Six fixes
- Three-digit timeouts: the custom timeout for temporary rules now accepts three-digit input. The changelog doesn't give a maximum value.
- Grouping counter: double-clicking a grouping counter no longer logs an unhandled exception.
- Duplicate update dialog: you no longer get two update dialogs when you check manually, leave the dialog open, and the automatic check also finds an update.
- Tray crash: the tray application no longer crashes when the program is locked and the service is stopped.
- Filter indicators: the Rules Panel now shows a visual cue when the "Show invalid rules" or "Show duplicate rules" filters are on.
- F1 help: F1 in the Main Panel now opens the correct user guide topic.
Is this a security update?
The changelog doesn't present it as one. It lists no CVE and no change to firewall behavior. That's worth stating because WFC's history includes real security fixes. Earlier changelog entries cover a remote code execution issue (CVE-2023-36631), an installer privilege escalation (CVE-2025-54569), and a named-pipe flaw that let low-privilege users turn the firewall off. This release is a usability and stability update.
Admins who deploy WFC to standard-user machines will still want to know that earlier release notes say changes now require elevation and a UAC prompt. Nothing in 6.39.0.0 changes that.
Requirements and a caveat on version details
The developer lists these requirements:
- .NET Framework 4.8.
- x86 and x64 versions of Windows 11, 10, 8.1, 8, 7, and Server 2012 through 2025.
- The Windows Firewall service enabled.
- The DNS Client service enabled, so notifications work properly.
The developer's own limitations note is also worth reading. Windows Firewall doesn't work well with software proxies, web filtering modules, NDIS drivers, or security software that redirects traffic to its own filter. If you run any of those, WFC's controls may not behave as expected.
Should you update?
If you use the tray app daily, probably yes. The tray-crash fix, the three-digit timeout fix, and the clearer filter indicators address everyday annoyances. The dark theme is cosmetic, but it's a visible improvement for anyone who has to look at the Rules Panel at night.
Back up your rules first. WFC lets you export and import rules, so a quick export before any update is cheap insurance. I haven't tested this build. The details above come from the developer's changelog and documentation and from Neowin's listing.