USG FLEX H Series - V1.39 Patch 0 Firmware Release

Zyxel_Melen

https://community.zyxel.com/en/discussion/comment/86082#Comment_86082

Hi @stgvn

Please help to send me a message for your organization's name and site's name. And enable Zyxel support access so we can check this issue.

https://community.zyxel.com/en/discussion/14234/nebula-how-to-turn-on-zyxel-support-access

Zyxel_Melen

https://community.zyxel.com/en/discussion/comment/86084#Comment_86084

Hi @tojeroman

This issue was caused by an error in the Release Note, and we sincerely apologize for the confusion it caused.

Currently, the H series models do not yet officially support IPv6 functionality. That ticket was primarily intended to fix a GUI display bug — at the time, although the device did not actually support IPv6, the GUI was incorrectly displaying IPv6-related information. We addressed and corrected this display issue accordingly.

mMontana

Any 1.39 adopters?

Which is your current upgrade experience?

astronout

We tried 1.39 patch 0 on our 700H and encountered unusual outbound connection issues, such as HTTP 504 Gateway Time-out errors and website connection failures. We’re going to roll back to 1.38.

Zyxel—please clearly state at the top of the release notes that this release is not stable (i.e., label it as beta). As written, it feels like a beta release without clear labeling.

astronout

Zyxel_Melen

Hi @astronout

Thanks for reporting this.

First, to clarify: 1.39 Patch 0 went through our standard QA and regression testing process before being officially released — it was not pushed out ahead of that process — so by definition it isn't labeled as a beta release.

That said, regarding the HTTP 504 / outbound connection issues you're seeing, we'd like to gather a few details so engineering can reproduce and investigate:

1. Syslog from when the issue occurred (with timestamps)
2. WAN interface configuration (PPPoE/DHCP/Static, any custom SNAT/Policy Route)
3. Whether Content Filter, IDP, Application Patrol, or similar features are enabled
4. Frequency of the issue and whether there's a pattern (e.g. specific sites/times)

Thanks.

Zyxel_Melen

https://community.zyxel.com/en/discussion/comment/86074#Comment_86074

Thank you for forwarding the email to us.

The email you received is Nebula Control Center Upgrade Notification, which is mainly notifying that Nebula Control Center will update to 20.10 From Jul.27, 2026 0:20 AM to Jul.27, 2026 2:00 AM UTC+0. And in this email, we notified USG FLEX H series has new firmware, but we won't upgrade your device once your setting is not "Latest" firmware type.

Hope this explanation helps.