As always feel free to add to this thread if have note-worthy additions about features/changes or you see other news or common problems popping up with the new release as it goes live to more users.
Tomorrow, April 29, is the second release day this month and Firefox 138 will get published.
These links will contain the usual bits of information for the new version once the release is live:
* release notes: https://www.mozilla.org/firefox/138.0/releasenotes/
* sec advisories: [https://www.mozilla.org/en-US/security/known-vulnerabilities/firefox/#firefox138]
* complete list of changes: [https://bugzilla.mozilla.org/buglist.cgi?j_top=OR&f1=target_milestone&o3=equals&v3=Firefox%20138&o1=equals&resolution=FIXED&o2=anyexact&query_format=advanced&f3=target_milestone&f2=cf_status_firefox138&bug_status=RESOLVED&bug_status=VERIFIED&bug_status=CLOSED&v1=mozilla138&v2=fixed%2Cverified&limit=0]
* developer notes: [https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/138]
As always feel free to add to this thread if have note-worthy additions about features/changes or you see other news or common problems popping up with the new release as it goes live to more users.
'''If you're a user yourself looking for help though, [https://support.mozilla.org/questions/new post in the support forum instead] pls :))'''
The 138 wiki is ready here. Also, for reference, here are Reddit and Lemmy threads for v138.
The 138 wiki is ready [https://wiki.mozilla.org/Support/Firefox138 here]. Also, for reference, here are [https://www.reddit.com/r/firefox/comments/1kan4tq/firefox_1380_releases_today/ Reddit] and [https://lemmy.ml/post/29291930 Lemmy] threads for v138.
Can Firefox version 138 and 139 be added to the Firefox "Customize this article" version picker ... with 138 as the default? Right now the version picker only goes up to 137. I filed a bug report on April 2 which is still open: Bug 1957915 - Add Firefox Version 138 (and 139?) to the "Customize this article" version picker and set Version 137 as the default
Can Firefox version 138 and 139 be added to the Firefox "Customize this article" version picker ... with 138 as the default? Right now the version picker only goes up to 137. I filed a bug report on April 2 which is still open: [https://bugzilla.mozilla.org/show_bug.cgi?id=1957915 Bug 1957915] - Add Firefox Version 138 (and 139?) to the "Customize this article" version picker and set Version 137 as the default
Can Firefox version 138 and 139 be added to the Firefox "Customize this article" version picker ...
Replied in the bug. Thanks again for bringing this up!
''AliceWyman [[#post-88880|said]]''
<blockquote>
Can Firefox version 138 and 139 be added to the Firefox "Customize this article" version picker ...
</blockquote>
Replied in the bug. Thanks again for bringing this up!
I don't see anything in our community forums so far, if you see something, please share here.
Hi folks,
FYI, there's a high priority bug in 138 related to Firefox new tab that we treat as an incident. More about that in the Firefox 138 wiki -> https://wiki.mozilla.org/Support/Firefox138#Known_incident(s)
I don't see anything in our community forums so far, if you see something, please share here.
Firefox 138 ignores these preference unless the user enables High Contrast mode (browser.display.document_color_use = 2):
* browser.anchor_color
* browser.visited_color
For a user that asked about how to solve this, I proposed a user style (in Stylus) but is there an easier solution?
Ref. https://support.mozilla.org/questions/1508993
I'm not sure what is happening with the article update.
* https://bugzilla.mozilla.org/show_bug.cgi?id=1957704
* https://blog.monotonous.org/2025/03/06/New-Contrast-Control-Settings/
Hey gang! I'm seeing some Youtube issues reported so wanted to flag that there is a bugzilla here: https://bugzilla.mozilla.org/show_bug.cgi?id=1963511
* https://support.mozilla.org/en-US/questions/1509062
* https://support.mozilla.org/en-US/questions/1508997
* https://support.mozilla.org/en-US/questions/1509061
# The blank page has been addressed with a dot release. Please shout if you continue to see user issue reports after updating to 138.0.1
# The YouTube issues have been categorized as an incident, and we will create a tag for tracking on SUMO: incident-1963511. https://bugzilla.mozilla.org/show_bug.cgi?id=1963511
Ok one more! Looks like bookmarks sidebar disappeared for a handful of users after update: https://bugzilla.mozilla.org/show_bug.cgi?id=1963549#c3
* https://support.mozilla.org/en-US/questions/1509220
* https://support.mozilla.org/en-US/questions/1509156
* https://support.mozilla.org/en-US/questions/1509087
* https://support.mozilla.org/en-US/questions/1509031
* https://support.mozilla.org/en-US/questions/1509006
Firefox 138 ignores these preference unless the user enables High Contrast mode (browser.display.document_color_use = 2):
browser.anchor_color
browser.visited_color
For a user that asked about how to solve this, I proposed a user style (in Stylus) but is there an easier solution?
Ref. https://support.mozilla.org/questions/1508993
I'm not sure what is happening with the article update.
Looks like the content request has slipped from our attention.
@Mandy do we know a workaround for the above issue?
''jscher2000 - Support Volunteer [[#post-88886|said]]''
<blockquote>
Firefox 138 ignores these preference unless the user enables High Contrast mode (browser.display.document_color_use = 2):
* browser.anchor_color
* browser.visited_color
For a user that asked about how to solve this, I proposed a user style (in Stylus) but is there an easier solution?
Ref. https://support.mozilla.org/questions/1508993
I'm not sure what is happening with the article update.
</blockquote>
Looks like the content request has slipped from our attention.
@Mandy do we know a workaround for the above issue?
In the Firefox hamburger menu go to Settings, then Privacy and Security and click on the Manage Data button. In the resulting dialog, search for youtube.com, select the row for site youtube.com and click "Remove Selected"
Opening a new tab with youtube.com should now work.
Thanks for flagging the color issue -- we will get to work on that content update asap!
Separately, here are steps to address the youtube issue:
* Ensure your uBlock Origin filters are up to date (see the [https://github.com/gorhill/ublock/wiki/Dashboard:-Filter-lists#update-now uBlock Origin Documentation] for how to do this.
* Close all YouTube tabs
* In the Firefox hamburger menu go to Settings, then Privacy and Security and click on the Manage Data button. In the resulting dialog, search for youtube.com, select the row for site youtube.com and click "Remove Selected"
* Opening a new tab with youtube.com should now work.
For a user that asked about how to solve this, I proposed a user style (in Stylus) but is there an easier solution?
I tried asking internally, but looks like we don't have an easier solution and you're correct to suggest the Stylus workaround.
''jscher2000 - Support Volunteer [[#post-88886|said]]''
<blockquote>
For a user that asked about how to solve this, I proposed a user style (in Stylus) but is there an easier solution?
</blockquote>
I tried asking internally, but looks like we don't have an easier solution and you're correct to suggest the Stylus workaround.
We're currently looking into this issue. If you find other similar questions, please consider sharing them here.
Hi folks,
It seems like we're having an issue with review checker not popping up on some users. I found [/questions/1510052], [/questions/1509842], and there's also [https://www.reddit.com/r/firefox/comments/1kd3msh/review_checker_gone_with_recent_update/ a Reddit thread] about this.
We're currently looking into this issue. If you find other similar questions, please consider sharing them here.
Sorry for spamming this 138 wiki! I have 2 updates:
YouTube Incident: youtube site reports are back down to normal levels after the spike due to this incident, so this incident is now marked as resolved. Our analysis is that Ublock origin shipped a bad filter which they have since fixed.
Sidebar bookmarks disappearing: It looks like there are workarounds on this Reddit thread
Sorry for spamming this 138 wiki! I have 2 updates:
* YouTube Incident: youtube site reports are back down to normal levels after the spike due to this incident, so this incident is now marked as resolved. Our analysis is that Ublock origin shipped a bad filter which they have since fixed.
* Sidebar bookmarks disappearing: It looks like there are workarounds on this [https://bugzilla.mozilla.org/show_bug.cgi?id=1963549#c25 Reddit thread]
to add on Mandy's shareout, we should have an incident tag for the bookmarks' sidebar issue -> incident-1963549. I've found a few more questions related to that today and they haven't been answered. If you see anything else, feel free to use the same tag so we can track this issue.
Also, it looks like the Tab Groups feature has shipped to 100% users as per yesterday. However, people who have telemetry turned off may not see it yet, but the team is going to fix this on a dot release planned for next week.
Hi folks,
to add on Mandy's shareout, we should have an incident tag for the bookmarks' sidebar issue -> [/questions/firefox?tagged=seg-incident-1963549 incident-1963549]. I've found a few more questions related to that today and they haven't been answered. If you see anything else, feel free to use the same tag so we can track this issue.
Also, it looks like the Tab Groups feature has shipped to 100% users as per yesterday. However, people who have telemetry turned off may not see it yet, but the team is going to fix this on a dot release planned for next week.
I also just shared an update about our weekly forum insights in the forum discussions here. Feel free to check out and let us know if there's something we can improve for the next update.
I also just shared an update about our weekly forum insights in the forum discussions [/forums/support-forum-contributors/717300?last=88929 here]. Feel free to check out and let us know if there's something we can improve for the next update.
Looks like we have another issue brewing in 138 impacting users on Windows 10 with touch screen ([https://bugzilla.mozilla.org/show_bug.cgi?id=1963666 bug1963666]).
I only found [/questions/1509018] so far, but let's keep an eye out!
Rename xulstore.json in your profile directory (e.g. to “xulstore.json.old”)
Restart firefox
From now on bookmarks should stay open if it was open when you quit/restart your browser.
Uncheck Clear history when firefox closes (or Browsing & download history from the custom settings…)Note: This is probably less recommended as it requires people to keep history around which they may have disabled if they have privacy concerns.
Go to settings / History
Uncheck Clear history when firefox closes
If the bookmarks sidebar is open when you restart it should reappear when restarting
Hey dream team! In addition to tagging the Bookmarks' Sidebar Issue with tag ''incident-1963549'', we can also share these known workarounds:
'''Renaming xulstore.json'''
# Shut down the browser
# Find your profile https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data
# Rename xulstore.json in your profile directory (e.g. to “xulstore.json.old”)
# Restart firefox
# From now on bookmarks should stay open if it was open when you quit/restart your browser.
'''Uncheck Clear history when firefox closes (or Browsing & download history from the custom settings…)'''
''Note: This is probably less recommended as it requires people to keep history around which they may have disabled if they have privacy concerns.''
# Go to settings / History
# Uncheck Clear history when firefox closes
# If the bookmarks sidebar is open when you restart it should reappear when restarting
I am going to create a bug report, but I am struggling to locate the issue (and I also cannot reproduce it). Is it ok to create a bug based on user reports only? I wouldn't do that, but the bug seems to be too much reported.
Hi guys,
Many users have reported taskbar not hiding in Full screen Mode:
* https://support.mozilla.org/en-US/questions/1509304 (with 23 have this problem)
* https://support.mozilla.org/en-US/questions/1510100
* https://support.mozilla.org/en-US/questions/1510109
I am going to create a bug report, but I am struggling to locate the issue (and I also cannot reproduce it). Is it ok to create a bug based on user reports only? I wouldn't do that, but the bug seems to be too much reported.
I am going to create a bug report, but I am struggling to locate the issue (and I also cannot reproduce it). Is it ok to create a bug based on user reports only? I wouldn't do that, but the bug seems to be too much reported.
Hi Denys,
Thanks again for bringing this to our attention. There are 2 possible bugs that may relate to this (bug1950441 and bug1965699. I've also added this to the Investigating section in our release wiki for Firefox 139 for everyone's awareness.
Desktop team wanted to see the outcome of the workaround suggested in /questions/1509304. So let's keep an eye on user comment on this.
''Denys [[#post-89014|said]]''
<blockquote>
I am going to create a bug report, but I am struggling to locate the issue (and I also cannot reproduce it). Is it ok to create a bug based on user reports only? I wouldn't do that, but the bug seems to be too much reported.
</blockquote>
Hi Denys,
Thanks again for bringing this to our attention. There are 2 possible bugs that may relate to this ([https://bugzilla.mozilla.org/show_bug.cgi?id=1950441 bug1950441] and [https://bugzilla.mozilla.org/show_bug.cgi?id=1965699 bug1965699]. I've also added this to the [https://wiki.mozilla.org/Support/Firefox139#Investigating Investigating section] in our release wiki for Firefox 139 for everyone's awareness.
Desktop team wanted to see the outcome of the workaround suggested in [/questions/1509304]. So let's keep an eye on user comment on this.
