For many organisations, a website is a long-term investment that continues to evolve over time. Even with regular enhancements, performance improvements, and proactive support, every website is still built on an underlying content management system (CMS) that has a defined lifecycle. When the CMS reaches end of life, it introduces risks that ongoing updates can’t fully address.
We’re currently speaking with many clients who are running on Kentico 13, which reaches end of life in December 2026, as well as older versions of Kentico that are already unsupported. If that sounds like you, this article explains what CMS end of life really means, why it matters, and what you should be doing next.
What does “CMS end of life” actually mean?
When a CMS reaches end of life (EOL), it means the vendor will no longer provide:
- Security patches or vulnerability fixes
- Bug fixes or technical updates
- Compatibility updates for browsers, servers, or integrations
- Official technical support
Your website may continue to function after this point, but it will effectively be frozen in time. Any new security risks, performance issues, or compatibility problems will be yours to manage alone.
For example, Kentico 13 has a defined support window (December 2026). Once that window closes, it will no longer receive security updates, even if new vulnerabilities are discovered.
What are the implications for my website?
An unsupported CMS isn’t just a technical inconvenience. It creates real, compounding risks for your organisation.
1. Security risks increase significantly
Security is the biggest concern.
When a CMS is no longer supported, any newly discovered vulnerabilities are left unpatched. This makes unsupported websites an easy target for:
- Data breaches
- Malware injections
- Website defacement
- Unauthorised access to forms, user data, or admin areas
For organisations handling personal, sensitive, or government-related data, this risk alone is often enough to justify a rebuild. Over time, the likelihood of an exploit increases, not decreases.
2. Compliance and governance risks
Many organisations have obligations around data protection, accessibility, and risk management. Running a website on unsupported software can:
- Conflict with internal IT or security policies
- Raise red flags during audits or reviews
- Create challenges around privacy and data protection compliance
Even if no incident occurs, the risk exposure still exists.
3. Compatibility issues over time
Web technologies don’t stand still. As browsers, servers, and third-party tools evolve, older CMS platforms can start to break or behave unpredictably. This can result in:
- Features or integrations no longer working as expected
- Editor or admin interfaces becoming unstable
- Increasing reliance on workarounds and custom fixes
These issues often surface gradually, making them harder (and more expensive) to deal with later.
4. Slower progress and rising maintenance costs
As a CMS ages, even small changes can take longer and cost more. Developers need to work around outdated frameworks, plugins, or dependencies, which reduces agility and increases technical debt.
Why do CMS platforms reach end of life?
CMS end of life isn’t a sign that you chose the wrong platform. It’s a normal part of modern software development.
Vendors retire older versions so they can:
- Focus on improving security and performance in newer products
- Adopt modern development frameworks and hosting models
- Respond to changes in user expectations, accessibility standards, and search behaviour
In the Kentico ecosystem, this evolution has led to Xperience by Kentico (also known as XbyK), which replaces older versions like Kentico 13 with a more modern, flexible architecture.
What are my options?
If your website is on Kentico 13 or an older, unsupported version, you generally have three realistic paths forward.
1. Do nothing (not recommended)
While your site may keep running for a while, this option carries the highest security and compliance risk. Over time, the cost and urgency of fixing problems usually outweigh the effort of planning properly.
2. Short-term risk management
Some organisations choose temporary measures, such as:
- Limiting changes to the site
- Increasing monitoring or security controls
- Applying custom patches where possible
This can buy time, but it doesn’t remove the underlying risk of running unsupported software.
3. Plan a website rebuild or migration
The most sustainable option is to plan a website migration to a supported CMS.
For many Kentico clients, this means rebuilding on Xperience by Kentico (XbyK) or moving to another modern CMS, such as WordPress, that better fits current needs.
While this requires investment, it also creates an opportunity to:
- Improve security and performance
- Refresh design and user experience
- Revisit information
- Build with modern SEO and Generative Engine Optimisation (GEO) principles in mind
What should I do next?
If your CMS is already end of life, or approaching it, the most important step is to start planning early.
Websites aren’t rebuilt overnight. A successful migration typically involves:
- Discovery and requirements definition
- Platform and architecture decisions
- Design and user experience updates
- Content review and migration
- Development, testing, and launch planning
Starting these conversations well before support ends gives you more control over timing, budget, and outcomes — and avoids rushed decisions driven by risk.
Plan early, reduce risk, and create opportunity
A CMS reaching end of life isn’t just a technical problem to solve. It’s a chance to step back and ensure your website is secure, future-ready, and aligned with how people search, engage, and interact today.
If you’re running Kentico 13, or an older unsupported version, now is the right time to start planning your next move. By acting early, you reduce security risk, avoid last-minute pressure, and turn a necessary rebuild into a strategic upgrade.
If you’d like help assessing your current platform or exploring options for website migration, we’re always happy to talk through what makes sense for your organisation. Contact us today to explore your options.