An alpha is a forecast, not a promise#
On October 1, 2026, the Tor Project released Tor Browser 16.0a13, the thirteenth test version of the next major Tor Browser. Every alpha release post opens with the same warning. The alpha channel is for testing only, it’s more likely to contain bugs that affect usability, security and privacy, and if you’re at risk or need strong anonymity, you should stay on the stable version.
That warning should be taken seriously, and it also shows you how to read everything that follows. An alpha isn’t a product. It’s a weather forecast. Some of what it shows is very likely to arrive, some is probable, and some might change or vanish before the stable release. Most articles about upcoming software treat all of this as a single list of “new features”, which makes forecasts sound like promises.
This article sorts what we know about Tor Browser 16 by how certain it is. First, what’s already in 16.0a13. Then what the alpha series strongly suggests for the stable version. Then what’s still genuinely uncertain, including the release date. Finally, whether you should try the alpha yourself, and how to prepare for the switch.
One piece of context first. The latest stable version is Tor Browser 15.0.25, released on October 12. For more on the stable line, see our Tor Browser 15.0.24 release notes and Tor’s September 2026 Security Fixes. Nothing in this post is a reason to leave the stable version today.
Certain: what 16.0a13 already contains#
These are the things that have been built, sent to testers and listed in the changelogs. They could still be adjusted, but they’re the firm part of the forecast.
A new engine underneath#
The most significant change is one you can’t see. Tor Browser 15 is built on Firefox ESR 140. Tor Browser 16 is built on Firefox ESR 153, and 16.0a13 already uses version 153.4.0esr on desktop and the matching GeckoView engine on Android.
The route there was unusual. In December 2025, the Tor Project announced, in a post called The Future of Tor Browser Alpha, that the 16.0 alphas would follow Firefox’s fast-moving regular releases instead of waiting for the next ESR. Mozilla explains the difference between the two channels in its support pages. So the early alphas tracked Firefox from version 146 onwards, one version at a time, until the alpha reached ESR 153 in the summer. The reasoning was practical. Moving Tor Browser’s privacy changes forward four weeks at a time is much easier to review than one big jump every year, and it spreads out work that used to be crammed into a few stressful months.
For you, the result is a full year of Firefox changes arriving in one go when 16.0 goes stable, but changes that testers have been living with, piece by piece, since early 2026.
A long list of things deliberately switched off#
A year of Firefox development brings new features, and many of them talk to servers, store data or reveal something about you. A large part of the 16.0 work is going through those features one by one and deciding which ones Tor Browser users should get. The changelogs show the results.
| In the alpha | What it is | Why it matters |
|---|---|---|
| Review of preference changes between Firefox 141 and 153 | A check of every new or changed setting in a year of Firefox | Nothing new should switch itself on quietly |
| Reporting API kept disabled | A web feature that lets sites receive reports sent from your browser | Fewer ways for sites to collect data about your browser |
| Fast path for skipping proxy resolution disabled | A shortcut that could let some lookups bypass the proxy | Keeps every connection going through Tor |
| Search suggestion features disabled for 16.0 | Firefox’s newer suggestion features | What you type stays in your browser |
| Profile backup disabled for 16.0 | Firefox’s new feature for backing up your profile | No copies of your browser data saved where you don’t expect them |
| Split view disabled for 16.0 | Firefox’s new side-by-side tab view | Not yet reviewed for Tor Browser’s privacy model |
| Harmful add-on URL blocking disabled | A Firefox mechanism for blocking certain add-on related addresses | Turned off in Tor Browser, as listed in 16.0a13 |
Several of those lines say “for 16.0”, which is worth noticing. The decision isn’t necessarily final. It means the feature hasn’t been reviewed thoroughly enough to ship yet, so the safe choice is to leave it off. That’s the right default for a browser like this, and it’s the kind of change most people never notice.
A redesigned settings page#
This is the change you will notice. Mozilla redesigned Firefox’s settings, and since 16.0a10 the alpha has used the new design by default. Tor Browser’s own settings have been moved across, including bridges, the security level settings, onion service authentication, which now sits alongside the password settings, and, as of 16.0a13, language preferences. The new Tor Browser manual has also been built into the browser itself.
If you’ve got used to where things are in Tor Browser 15, expect to look for them again in 16. The settings themselves will mostly be the same. Their places won’t.
Onion site fixes#
Two desktop fixes in 16.0a13 are about onion sites specifically. One stops the browser showing a confusing certificate check and error when an onion site uses a self-signed certificate. That’s common for onion sites, because the onion address itself already proves which server you’ve reached. The other fixes a crash when you click “Learn more” on the error page shown when an onion site can’t be reached. Both also reflect a broader trend, as more onion sites use HTTPS on top of the onion address, something we explain in How to Verify an Onion Address Is Official.
Android details#
On Android, 16.0a13 fixes a bug where selected text could only be shared once, adds settings for choosing where downloads are saved, and turns off bookmark importing until that feature is stable. Small changes, but they’re the kind that decide whether a phone browser feels finished.
Likely: what the alpha points to for 16.0 stable#
The next part of the forecast comes from what the Tor Project has said publicly about its plans, combined with what the alpha series has done consistently for months. None of it is guaranteed, but it would be surprising if it changed.
Stable 16.0 will run on ESR 153, and stay there#
The Tor Project’s December 2025 post was clear. Tor Browser 16.0 will stabilise on Firefox 153 and, once released, follow the ESR channel for the rest of its life. In practice, 16.0 will behave the way 15.0 does today, with regular security updates on a stable base rather than new Firefox features every month. The alpha channel, meanwhile, will move on to whatever comes next.
There won’t be a 15.5#
The Tor Project used to release two feature versions a year, a .5 release in spring and a .0 release in autumn. Under the new model there’s only one. The same post said directly that there would be no Tor Browser 15.5. So 16.0 is the next time the stable channel gets a major set of new features.
Older platforms will lose support#
The 16.0 alpha series has already dropped two groups of devices, following Firefox. It no longer builds for Linux or Android on 32-bit x86 processors, and it needs at least Android 8.0. The stable 15.0 series has also been preparing 32-bit Linux users for the end, with a final warning message added in 15.0.24. It would be very surprising if stable 16.0 restored support that the whole alpha series has dropped.
If you’re on one of those platforms, your Tor Browser will keep getting 15.0 security updates until that series ends, and then stop. For phones, our guide to Using Tor on Android and iPhone covers the alternatives. For older computers, Tails on a 64-bit machine is the usual answer, as covered in Tails 7.14.
Most switched-off features will stay off#
The features disabled “for 16.0” in the alpha will very likely stay disabled in the first stable release. Some may come back in later versions after review. That’s how Tor Browser has always handled new Firefox features, and the alpha changelogs give no hint of a different approach.
The new look will ship#
The redesigned settings have been the alpha default since 16.0a10 in August, and the team has spent several releases moving Tor Browser’s own settings into them. That’s a lot of effort to throw away, so expect 16.0 stable to look noticeably different from 15.0 when you open its settings.
The forecast at a glance#
| What | Confidence | Why |
|---|---|---|
| Based on Firefox ESR 153 | Very high | Already the base of the alpha, and announced by the Tor Project |
| No Tor Browser 15.5 | Very high | Stated in the Tor Project’s own plan |
| New settings design | High | Default in the alpha since August, with Tor’s own settings moved over |
| No 32-bit x86 Linux or Android, Android 8.0 or later only | High | Dropped for the whole alpha series, following Firefox |
| New Firefox features like split view and profile backup turned off | High | Disabled “for 16.0” in the alpha |
| Exact release date | Low | The original target has already passed, and no new date has been announced |
| Every alpha change reaching stable unchanged | Low | That’s what alphas are for |
Still open: what nobody can promise yet#
The last part of the forecast is where honest answers start with “we don’t know”.
The release date#
In December 2025, the Tor Project expected Tor Browser 16.0 to reach stable about halfway through the third quarter of 2026, which would have been around August. As of October 13, the latest version is still an alpha, and no new date has been given. That’s not unusual for a release with this much work in it, but it means any date quoted elsewhere is a guess.
There is a firm limit, though, and Mozilla sets it. As the same Tor Project post explains, Mozilla overlaps support for the old and new ESR versions for only four releases, about sixteen weeks. Once support for ESR 140 ends, Tor Browser 15.0 stops getting security fixes from Firefox. ESR 153 arrived in the summer, so the window is narrowing, and Tor Browser 16.0 stable has to be out before it closes. Mozilla was still issuing ESR 140 fixes on September 29, and Tor Browser 15.0.24 picked them up, so 15.0 is still safe today.
In other words, don’t plan around a date. Plan around the fact that it’s coming soon, and that 15.0 won’t be supported for long after it does.
Whether the new way of building alphas continues#
The Tor Project described following Firefox’s fast releases in the alpha channel as an experiment. It said that if serious problems came up, the team could go back to the old way the following year without stable users noticing much. The team has also acknowledged the trade-offs. Following Firefox closely means alpha testers get new Firefox bugs quickly too, and alpha security updates may sometimes lag if a rebase is hard. Whether the experiment becomes permanent will probably be decided after 16.0 ships.
Which switched-off features come back#
Split view, profile backup and the new search suggestions are off “for 16.0”. Some may return in later 16.x releases after review. Others may stay off for good if they can’t be made to fit Tor Browser’s privacy model. Nobody outside the team can say which yet.
What changes under the hood for Tor itself#
Tor Browser 16 alphas use the same Tor software as stable, currently the 0.4.9 series, which has had several security releases since September. Tor’s newer implementation, Arti, keeps developing. Arti 2.7.0 was released on October 1, and Arti already powers the Tor Project’s Tor VPN beta on Android. But the 16.0 alpha changelogs say nothing about moving Tor Browser itself to Arti, so there’s no reason to expect it in 16.0.
What’s leaving#
Forecasts are about arrivals, but 16.0 also means some departures, and those are close to certain.
- Tor Browser 15.0. It will keep getting security updates until ESR 140 support ends, then stop. Everyone on 15.0 will need to move to 16.0.
- 32-bit x86 Linux and Android. No builds in the 16.0 series.
- Android 5.0, 6.0 and 7.0. The 16.0 series needs Android 8.0 or later.
- Some familiar layouts. The settings page will look different, and some options will be in new places.
Should you try the alpha?#
For most readers, no. The Tor Project says so in every alpha release post, and it’s worth repeating plainly. If you rely on Tor Browser to protect you, if you’re at risk, or if you just need a browser that works every time, stay on stable. The alpha is more likely to have bugs that affect your privacy and security, and under the new model it may sometimes get Firefox security fixes later than stable does.
But “most readers” isn’t everyone. Alpha testers are how bugs get found before they reach millions of people, and the Tor Project actively asks for testers. The alpha makes sense if you fit one of these descriptions.
| You might try the alpha if you | Why it helps |
|---|---|
| Run an onion site | You can check your site works with the next browser before your visitors get it |
| Build websites or web apps | You can catch problems with the new engine and Tor Browser’s settings early |
| Translate Tor Browser or write about it | The new settings design changes a lot of text and screenshots |
| Are curious, technical and not at risk | Every bug you report is one fewer in the stable release |
How to test without putting yourself at risk#
- Keep stable as your real browser. The alpha installs as a separate program on desktop and a separate app on Android. Use stable for anything that matters, and the alpha only for testing.
- Get it from the Tor Project only. The alpha has its own download page. Alpha versions also appear on APK mirror sites, which is exactly where fakes hide, as we explain in Fake ‘Dark Web’ Apps in 2026.
- Verify it like any other download. Alpha releases are signed the same way as stable ones, including with the new signing subkey introduced in September. Our guide How to Download and Install Tor Browser Safely covers the process.
- Don’t put anything sensitive in it. No logins you care about, no contact with sources, nothing you couldn’t afford to have leak.
- Test the things that are changing. Open the new settings and find your way around. Set the security level to Safest and see what breaks. Visit a few onion sites from our Official Onion Mirrors Directory. If you use bridges, check they still connect, and see Bridges, Snowflake and WebTunnel if they don’t.
- Report what you find. The Tor Project’s bug and feedback page explains how. A short, specific report, saying what you did, what you expected and what happened, is worth more than a long complaint.
If that sounds like more effort than you want to spend, that’s completely fine. Waiting for stable is the right choice for most people, and you’ll get everything worth having, after the testers have found the problems.
Getting ready for 16.0 stable#
You don’t need to do anything dramatic before Tor Browser 16 arrives. A few minutes now will make the switch smoother.
- Make sure you’re on the current stable release. That’s Tor Browser 15.0.25, released on October 12. It updates Tor to 0.4.9.14, backports security fixes from Firefox 158, and includes a build change to use a new Windows signing certificate, which should help with the signing warnings Windows users saw in September. Check your version under Help, then About Tor Browser, and restart if an update is waiting.
- Check your platform will be supported. You’ll need a 64-bit computer, or an Android phone running Android 8.0 or later. If you’re not sure, now is a good time to find out, while 15.0 is still getting updates.
- Note your settings. If you’ve changed your security level, set up bridges or changed the language, write down what you chose. The settings should carry over, but they’ll be in new places, and it helps to know what you’re looking for.
- Back up bookmarks you care about. Tor Browser forgets your history by design, but it keeps bookmarks. Exporting them before any major update is a sensible habit, especially on Android, where bookmark importing is switched off in the alpha.
- Let it arrive the normal way. When 16.0 is ready, Tor Browser will offer it as an update. You won’t need to download it from anywhere else, and you shouldn’t.
- Be wary of “early” downloads. Any site, video or message offering Tor Browser 16 before the Tor Project announces it is a fake. If in doubt, check the Tor Project blog, and see our guide to fake ‘dark web’ apps.
- Expect a few differences. A year of Firefox changes means some sites may behave a little differently, and the settings will look new. If something important breaks at your usual security level, report it rather than lowering the level for good.
If you use Tails, it should move to Tor Browser 16 in a Tails release shortly after the stable version comes out, as it does with every Tor Browser update. The Tails news page announces each release, and our Tails 7.14 post shows how Tails tracks Tor Browser releases. On iPhone, Onion Browser isn’t built on Tor Browser, so 16.0 doesn’t directly affect it.
We’ll publish full release notes when Tor Browser 16.0 stable is out, in the same style as our Tor Browser 15.0.24 release notes.
Where to go next#
- Want the details of the current stable line? Read our Tor Browser 15.0.24 release notes.
- Want to know what September’s Tor fixes mean for you? Read Tor’s September 2026 Security Fixes: What to Update.
- Choosing a security level, or testing one in the alpha? See Tor Browser Security Levels: Standard vs Safer vs Safest.
- On an older phone? Read Using Tor on Android and iPhone.
- Installing or verifying any version? Follow How to Download and Install Tor Browser Safely.
- Running an onion site you want to test? Start with What Is an Onion Service?
- Want the Tor Project’s own sites over onion? See Tor Project’s Official Onion Sites.
- New here? Find out how we work in About thehidden.wiki.
Sources#
- New Alpha Release: Tor Browser 16.0a13, Tor Project blog, October 1, 2026
- The Future of Tor Browser Alpha, Tor Project blog, December 1, 2025
- New Alpha Release: Tor Browser 16.0a10, Tor Project blog, for the new settings design and the features disabled for 16.0
- Tor Browser 16.0a11 alpha release, ThreatCluster summary, September 2026
- New Release: Tor Browser 15.0.25, Tor Project blog, October 12, 2026
- Arti 2.7.0 released, Tor Project blog, October 1, 2026
- Become a Tor Browser tester, Tor Project community portal
- Choosing a Firefox update channel, Mozilla Support, on Rapid Release and ESR