The Different Flavors of Kendo UI and Kendo Licensing Terms
Flavors of Kendo UI
Kendo has a free version of Kendo Core, which is open source, Kendo Professional, which is a paid license, and Kendo DevCraft, a premium commercial license that provides all of the Kendo Professional functionality and offers additional .Net support.
For a breakdown of the functionality offered in the different versions see https://github.com/telerik/kendo-ui-core#features-of-kendo-ui-core.
Progress's licensing model for Kendo UI is a little bit confusing. I am not a lawyer, but I have purchased an annual developer license for over a decade now and the legal team where I work, the University of Washington, has researched the EULA thoroughly. A decade ago, this legal team was able to remove one of the vague distribution provisions of the EULA with Telerik before we purchased this software.
I have also called Telerik on multiple occasions to discuss licensing issues as I have open-sourced my own personal projects using Kendo Core. The Telerik representatives were often vague when I asked them detailed questions, but I made sure to try to get as much information as possible from them before releasing Galaxie Blog 1.0 several years ago.
As I understand it- if you are going to use any version other than the open-source version of Kendo Core- you are bound by the end-user license agreement. This agreement states that if a developer uses the professional version for more than 30 days, each developer must purchase an annual developer license. Once the license has been obtained, the developer can continue to use the software perpetually as long as they remain at, or under, the latest version that was available at the time of the license window, which typically lasts for a year.
For example, if you purchased your license in July of 2022 you can continue to use the latest version at that time which is v2022.2.62. Generally, there are 2-3 new versions that come out per year, unless you decide not to make another annual purchase, you can probably update your version at least twice before your annual license term expires.
However, the developer is not allowed to distribute the code¹.
'Distribute' is a tricky term, but this is how I have come to understand it- at any time, even after the expiration of the subscription window, the developer can create new applications for their customers and place them on multiple servers, but they can't make the application publically available by open-sourcing it. Also, the end-users cannot alter the Kendo UI portion of the licensed code. The owner of the license needs to inform the customer that they must buy their own license if they were to modify the Kendo UI portion of the code. Only a developer who owns a license (or is in the 30-day trial period) can modify the Kendo UI portion of the code.
The only way around this is to use Progress's open-sourced version of Kendo Core.
Kendo Core uses a permissive Apache 2.0 license that allows you to freely use and distribute your code with no license restrictions. Kendo Core offers most of the major Kendo widgets, but it does not offer the Kendo UI grids or other advanced widgets. That said, I have incorporated other open source libraries to fill in the functional gaps that are missing in Kendo Core and will blog about them in future posts.
If you are considering using Kendo UI, you should review the Kendo licensing terms on your own.
- jQuery Kendo UI End User License Agreement
- Kendo UI Purchasing and Licensing FAQ
- nopCommerce forum post
¹See section 4.A.2. Redistribution under Developer License
This entry was posted on July 8, 2022 at 8:59 PM and has received 241 views.