Silverstripe CMS 6.1 End of Life: October 18, 2026

By Scott Bissett  ·  Published: October 9, 2026  ·  Reference guide  ·  Dates read on October 9, 2026 from Silverstripe's roadmap and support timeline data (the silverstripe/roadmap repository on GitHub), and the release policy, upgrade guide and 6.2.0 changelog at docs.silverstripe.org.

Silverstripe CMS 6.1 reaches end of life on October 18, 2026. The date comes from Silverstripe's own data: the silverstripe/roadmap repository holds the file behind the Silverstripe CMS roadmap and support timeline, and it gives 6.1 a release date of October 13, 2025, a Partial support phase starting April 17, 2026, and a support end of October 18, 2026. For the last six months a 6.1 site has received only high and critical security fixes. After the end-of-life date it receives none, and the fix is a minor upgrade to CMS 6.2 inside the same CMS 6 major series.

Silverstripe's support phases, in Silverstripe's words

Silverstripe's release policy says each Silverstripe CMS version "progresses through three defined support phases". The policy applies to Silverstripe's commercially supported modules, the set that together makes up a Silverstripe CMS release.

• Full support starts when the version is released. Security vulnerabilities "at all impact levels" are addressed, bug fixes are made provided they do not change existing public API, and enhancements are allowed. For a standard version it lasts approximately six months, "until the next minor release is performed".
• Partial support follows. Only "high and critical impact security vulnerabilities (those with a CVSS score of 7.0 or above)" are addressed. No bug fixes, no new features, no enhancements. For a standard version it lasts six months.
• End-of-life comes when Partial support ends: no security fixes, no bug fixes. The policy's own note: users on end-of-life versions "are strongly encouraged to upgrade to a supported version".

Minor releases are "targeted for April and October each year", so a standard version like 6.1 is supported for about a year in total: six months of Full support, then six months of Partial support. The last minor of each major series, such as CMS 5.4, gets an extended support length instead, and the policy adds that only two major version series are officially supported at any one time.

Where each current version stands

Exact days below are the ones Silverstripe's roadmap data gives as a day. Where the data gives only a month, the cell carries Silverstripe's planned month in words; those months are plans and can move. Each version links to its live status page here.

CMS 5.4 is the last minor of CMS 5, so it has the extended support length; the release policy says it "will remain in partial support until CMS 7.0 is released". Every Silverstripe version back to 2.3 is on our Silverstripe lifecycle page.

Key dates

• October 13, 2025: Silverstripe CMS 6.1 released.
• April 14, 2026: Silverstripe CMS 6.0 end-of-life.
• April 17, 2026: Silverstripe CMS 6.2 released.
• April 17, 2026: CMS 6.1 moves from Full support to Partial support.
• October 18, 2026: CMS 6.1 end-of-life. This page.
• October 2026, planned: Silverstripe's roadmap lists CMS 6.3 for this month. When it is released, CMS 6.2 moves to Partial support.

What Partial support means for a 6.1 site

Silverstripe CMS is shipped as a set of modules (silverstripe/framework, silverstripe/cms, silverstripe/admin and others), and fixes reach a site as patch releases of those individual modules. The release policy calls patch releases "the delivery mechanism" for its support commitments. For a site on 6.1, Partial support has meant three things since April 17, 2026:

• Security fixes only above the line. A vulnerability rated 7.0 or higher under CVSS gets a patch for 6.1; a medium or low one does not. As an example of where that line falls, the 6.2.0 changelog lists one security fix, CVE-2026-24749, a DBFile permission bypass rated Medium.
• No bug fixes. A defect found in 6.1 is fixed in a supported version, not in 6.1.
• Fixes arrive in set windows. The policy schedules security patch windows in January, April, July and October, lined up with the expected minor releases. A reported vulnerability waits for the next window when Silverstripe is confident it is not being actively exploited in the wild.

After October 18, 2026 even the high and critical fixes stop. The site keeps running, but any later security patch for the modules it uses ships only for supported versions.

How to check what you are running

From the project root, ask Composer for the installed framework version:

composer show silverstripe/framework

Read the versions line. The framework version follows the CMS version: the 6.2.0 changelog lists silverstripe/framework 6.2.0 and silverstripe/recipe-cms 6.2.0 as the versions included in CMS 6.2.0. A version starting 6.1. means the site is on the line ending October 18, 2026. Without Composer at hand, open composer.lock and find the entries named silverstripe/framework and silverstripe/recipe-cms; their version fields give the same answer. The version constraint for the recipe is in the root composer.json.

For many sites at once, an SBOM records Composer packages as pkg:composer purls; our SBOM end-of-life audit guide shows how to read them, and our EOL Checker and API resolve the result against the dates above.

Upgrade path: 6.1 to 6.2

1. Know what kind of upgrade it is. 6.1 to 6.2 is a minor upgrade in the same CMS 6 major series. The release policy says minor releases are backward compatible "within their Silverstripe CMS major version series" and are "generally more straightforward to manage than major release upgrades". Silverstripe's upgrade guide still cautions that APIs may change between minor releases and that a minor upgrade can take a day of work on a small site.
2. Change the recipe constraint. Silverstripe's guide to keeping projects up to date says to open the root composer.json, find the recipe lines such as silverstripe/recipe-cms, and change them to the version named in the changelog, along with any other module that has a new version:

   "require": {
       "silverstripe/recipe-cms": "~6.2.0"
   }

3. Update and commit the lock file. Run composer update, then commit both composer.json and composer.lock and deploy through your usual workflow, as the guide describes.
4. Read the 6.2.0 changelog for your code. The 6.2.0 changelog lists changes to the admin section's HTML markup (custom admin CSS or JavaScript that targets those elements needs checking), deprecates the <base> tag with a configuration switch to remove it, and adds PHP 8.5 support across the supported modules, with the note that some third-party modules may not support PHP 8.5 yet.
5. Plan the next step now. 6.2 is in Full support only until CMS 6.3 is released, which Silverstripe's roadmap plans for October 2026, and the roadmap plans 6.2's end-of-life for April 2027. Moving to the newest CMS 6 minor each April and October keeps a site out of Partial support altogether.
6. Check PHP in the same pass. The PHP version under the site has its own end-of-life date; see our PHP lifecycle page.

Frequently Asked Questions

Related

• Silverstripe 6.1 — the live status page with its EOL Risk Score
• Silverstripe — every version's dates
• Silverstripe 6.2 · Silverstripe 5.4 · Silverstripe 6.0 — the neighbouring versions
• PHP · PHP end of life — the runtime under every Silverstripe site
• Symfony — common PHP libraries Silverstripe CMS uses
• SBOM end-of-life audit — finding Composer packages in an SBOM
• 2026 EOL calendar — every dated end of support this year
• Silverstripe release policy — the vendor page the support phases were read from
• How we verify our dates — the rules every number on this site is held to