Release History

History of Stable C1 CMS Versions

Important. As of September 21, 2016, we have changed our project name from "Composite C1" to "C1 CMS Foundation". Existing releases up to, and including, v5.2 have not been renamed.

The table below lists public releases of C1 CMS (formerly known as Composite C1) version 2.0 or later.

By clicking the version name, you will open the version's page at

For detailed release notes, please click "Read more" where available.

Version NameRelease dateVersion number

C1 CMS 6.12017-04-266.1.6325.31805

What's New? This is a minor release that introduces several updates in search and language functions, it includes fixes and performance improvements and it allows developers to use C# 7.0 features. Read more

C1 CMS 6.02017-02-086.0.6248.33161

What's New? This is major release minor improvements that includes built in search, a new visual components feature, more ways to customize the console and valuable tooling like WAMP, React/Redux and built in DI support.  Read more

C1 CMS 5.52016-11-145.5.6162.32841

What's New? This is a service release with minor improvements that includes more stable previews of CMS functions in Visual Editor, a faster initial setup of the CMS and support for data updates with add-ons.  Read more

C1 CMS 5.42016-11-035.4.6150.25005

What's New? This is a minor release that follows up on the recent v. 5.3 release. It introduces support for bulk uploading files to the website file system, a selection counter on the hierarchical tree selector and a new Nightwatch API command for file upload tests. Read more

C1 CMS 5.32016-10-185.3.6135.33075

What's New? This is the first release after changing the name to C1 CMS from Composite C1. It features duplication of pages and data and Nightwatch framework integration for automated end-to-end testing. The minimum .NET Framework version has been increased to 4.6.1. Read more

Composite C1 5.22016-09-065.2.6093.24082

What's New? Version 5.2 introduces a number of API level features and data layer changes, which enable storing multiple versions of data. Read more

Composite C1 5.12016-08-125.1.6027.17836

What's New? Version 5.1 is a service release that comes with new features such as bulk publishing, time zone support, some UI enhancements, support for overriding the UI and logic behind actions (add, edit, publish etc) on pages/data, new widgets as well as fixes for issues found in the v5 release and other minor improvements and optimizations. Read more

Composite C1 5.02015-12-155.0.5827.21806

What's New?  V5 is the third major release since Composite C1 went open-source 5 years ago and comes packed with a lot of UI / UX improvements / new features such as the brand new CMS Console and the browser view, and improved developer tooling such as much better support for MVC, dependency injections on CMS Function parameters,  mapping data items to URLs to tree elements. Read more

Composite C1 4.32015-03-184.3.5555.25838

What's New? This latest stable release does much for performance improvements and enjoys a good deal of new features, including scheduled data publishing, native content editing experience with RTL languages like Arabic, enhanced password policy options, image resizing options in Razor, hooking into ASP.NET Full Page Caching key generation and more. Read more

Composite C1 4.2 Update 12014-06-234.2.5287.17495

What's New? The latest update contains a number of improvements and bug fixes and is a recommended update to 4.2.

Composite C1 4.22014-05-274.2.5249.32246

What's New? The latest stable release of Composite C1 comes packed with even more new features: CMS Function previews in Visual Editor, user-friendly editing of CMS Function properties, and the new responsive starter site called "Venus", editing pages on iPads, ASP.NET Razor 3.1.1 support by default, a new widget to select glyph icons, the server log now in the System perspective with more to log and audit, a new security permission "Configure" and more. Read more

Composite C1 4.12013-11-074.1.5058.34326

What's New? Another stable release of Composite C1, which equip both developers and end users with even more features like drag-and-drop for images and files from the desktop into page content, support for Composite Form Builder, the "Open Cph" Starter Site upgraded to Bootstrap 3, Internet Explorer 11 support, Microsoft .NET 4.5 made required, a new "Static Datatypes" folder on the Data Perspective, a 100% customized UI for the "Function Call Editor" for custom CMS Functions, and many more. Read more

Composite C1 4.02013-07-064.0.4897.31550

What's New? The 2nd big milestone release since Composite C1 open-sourced in October 2010, adding more power to end users with features like the block selector, searchable drop-downs, freehand image resizing, new Starter sites, and more, and to developers with features like built-in Razor and User Control functions, Razor and Master Page templates, page template features, data tree ordering, and many more. Read more

Composite C1 3.22012-04-273.2.4497.34793

What's New? The major service release to 3.0, adding "Save and Publish" combo button that enable easy opt-out of publish workflow. German and Chinese translations of the admin UI. Support for plugging in external media data bases (like SharePoint or images from Facebook). HTML5 video streaming support. Compatible with .NET 4.5 and Visual Studio 2012. Easy conversion to Visual Studio Web Application projects. Read more

Composite C1 3.12012-01-183.1.4400.42718

What's New? A service release to 3.0, adding support for spell checking (when using Mozilla Firefox with dictionaries installed) and .less file edit support. Also fixes issues reported on 3.0.

Composite C1 3.02011-12-073.0.4358.29126

What's New? Being a major release 3.0 contain a lot of improvements: URLs are short and without ‘.aspx’, Seamless ‘Paste from Word’, instant image and file upload from editors, in place image resizing, UX improvements reducing clicking, ASP.NET Razor support,  full Windows Azure and SQL Azure support, and a lot more. Read more

Composite C1 2.1.12011-04-072.1.4113.99

What's New? HTML5 support and bugfixes.

Composite C1 2.12011-03-112.1.4087.22991

What's New? IE9, Chrome support, SQL Server migration, 30 day trials on premium features, new code and customizable html editor, Windows Azure cloud support, build in performance profiling, ASP.NET .master page templates, expanded API, faster! Read more

Composite C1 2.0 SP 12010-10-252.0.3947.24461

What's New? New source code editor (SkyWriter),  faster page preview, CRUD functions for custom data types,  inline C# functions, cleaned-up localization files (ready for GUI translators), Custom URL action with data-driven parameters, a few new functions (page cache control, path to the Composite C1 application root, new random GUID etc),  setup check and Windows Azure-related fixes.  Read more

Composite C1 2.0 Patch 12010-10-032.0.3927.42711

What's New? Bug fixes

Composite C1 2.02010-09-292.0.3919.5834

What's New? The first public release of Composite C1 as a free open-source CMS.

second big milestone release since we open-sourced our CMS back in October 2010