Our security preview releases provide early access to Android Security Bulletin patches prior to the official disclosure. Our current security preview releases provide the current revision of the November 2025 and December 2025 patches for the Android Open Source Project. We recommend enabling this.

The only difference between our regular releases and security preview releases are the future Android Security Bulletin patches being applied with any conflicts resolved. The downside of security preview releases is we cannot provide the sources for the patches until the official disclosure date.

The delay for being able to publish the sources is why we're now going through the significant effort of building 2 variants of each release. Our most recent 3 releases have both a regular and security preview variant:

2025092500 and 2025092501
2025092700 and 2025092701
2025100300 and 2025100301

You can enable security preview releases via Settings > System > System update > Receive security preview releases.

Our plan is to keep it off-by-default with a new page added to the Setup Wizard which will have it toggled on as a recommendation. We'll prompt users on existing installs to choose.

We're maintaining the upcoming Android security patches in a private repository where we've resolved the conflicts. Each of our security preview releases is tagged in this private repository. Our plan is to publish what we used once the embargo ends, so it will still be open source, but delayed.

The new security update Android is using provides around 3 months of early access to OEMs with permission to make binary-only releases from the beginning. As far as we know, GrapheneOS is the first to take advantage of this and ship the patches early. Even the stock Pixel OS isn't doing this yet.

During the initial month, many patches are added or changed. By around the end of the month, the patches are finalized with nothing else being added or changed. Our 2025092500 release was made on the day the December 2025 patches were finalized, but we plan to ship the March 2026 patches earlier.

Previously, Android had monthly security patches with a 1 month embargo not permitting early releases. For GrapheneOS users enabling security preview releases, you'll get patches significantly earlier than before. We'd greatly prefer 3 day embargoes over 3 month embargoes but it's not our decision.

Android Security Bulletin (ASB) for October 2025 is empty:

https://source.android.com/docs/security/bulletin/2025-10-01

However, you can see Samsung has a list of ASB patches for their October 2025 release exclusive to flagships:

https://security.samsungmobile.com/securityUpdate.smsb

It's a small subset of the December 2025 patches.

Android now discloses patches around 3 months prior to their inclusion in a bulletin requiring them to raise the Android security patch level. However, OEMs are allowed to ship the patches as soon as they're receive. We're doing this in our security preview release, but with the full set of patches.

Our initial security preview release on September 25th with the November/December patches included 1 Critical severity patch and 54 High severity patches, which is the full subset applicable to Android 16. In the past couple days, 5 patches applicable to Android 16 were added and 1 was retracted.

December 2025 patches from the past couple days have been included and the January 2026 preview is now available.

Our next release coming today provides a choice to use our security preview releases in the initial setup wizard with a notification for existing users. Opting into it is recommended.

https://discuss.grapheneos.org/d/27068-grapheneos-security-preview-releases provides more information on our security preview releases. The reason we're providing both regular and security preview releases is because we're required to wait to the embargo end date to publish the source code for the patches in the future bulletins.