From 39f132491a4bce35cfd03bbe0d0f18c6b8ef8c99 Mon Sep 17 00:00:00 2001 From: Brian Smith Date: Mon, 31 Aug 2026 15:19:38 +0200 Subject: [PATCH 1/2] relnote(155): Add details about happy_eyeballs_enabled --- release-notes/firefox.md | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/release-notes/firefox.md b/release-notes/firefox.md index 23629f3..e12f8f1 100644 --- a/release-notes/firefox.md +++ b/release-notes/firefox.md @@ -22,6 +22,10 @@ Firefox ESR 153 is the current ESR. - Captive portal and network connectivity checks now use `firefox-portal-detection.com` instead of `detectportal.firefox.com`. Network allowlists and proxy rules naming the old domain need updating. Firefox 155 only. ([bug 2049252](https://bugzil.la/2049252), [bug 1898891](https://bugzil.la/1898891)) +- Some sites may load slowly or fail to load on networks that block UDP. + This can affect corporate networks where a proxy or firewall blocks QUIC as part of TLS inspection. + To work around it, set `network.http.happy_eyeballs_enabled` to `false` with the `Preferences` policy. + A fix is planned for a dot release the week of 7 September. ([bug 2063452](https://bugzil.la/2063452)) ### Fixes From 422e9ae03fa84f06aa4de8f7d5ca9fef806b7ce9 Mon Sep 17 00:00:00 2001 From: Brian Smith Date: Mon, 31 Aug 2026 15:22:47 +0200 Subject: [PATCH 2/2] relnote(155): Add details about happy_eyeballs_enabled --- release-notes/firefox.md | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/release-notes/firefox.md b/release-notes/firefox.md index e12f8f1..6465b0d 100644 --- a/release-notes/firefox.md +++ b/release-notes/firefox.md @@ -22,10 +22,6 @@ Firefox ESR 153 is the current ESR. - Captive portal and network connectivity checks now use `firefox-portal-detection.com` instead of `detectportal.firefox.com`. Network allowlists and proxy rules naming the old domain need updating. Firefox 155 only. ([bug 2049252](https://bugzil.la/2049252), [bug 1898891](https://bugzil.la/1898891)) -- Some sites may load slowly or fail to load on networks that block UDP. - This can affect corporate networks where a proxy or firewall blocks QUIC as part of TLS inspection. - To work around it, set `network.http.happy_eyeballs_enabled` to `false` with the `Preferences` policy. - A fix is planned for a dot release the week of 7 September. ([bug 2063452](https://bugzil.la/2063452)) ### Fixes @@ -35,6 +31,14 @@ Firefox ESR 153 is the current ESR. - Locking legacy preferences such as `pref.general.disable_button.default_browser` didn't disable the corresponding controls in Firefox Settings, following the Settings rewrite. ([bug 2056928](https://bugzil.la/2056928), [bug 2055887](https://bugzil.la/2055887)) - Firefox reported that it could pin itself to the taskbar when Windows Group Policy blocked pinning. Firefox 155 only. ([bug 2059920](https://bugzil.la/2059920)) +### Known issues + +- Some sites may load slowly or fail to load on networks that block UDP. + This can affect corporate networks where a proxy or firewall blocks QUIC as part of TLS inspection. + To work around it, set `network.http.happy_eyeballs_enabled` to `false` with the [`Preferences`](/reference/policies/preferences/) policy. + A fix is planned for the next dot release. + Does not apply to the ESR. ([bug 2063452](https://bugzil.la/2063452)) + ## 154 _Released 18 August 2026._