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What has changed from Umbraco 8 to 9?

The top 5 changes you should be aware of as a Developer

Warren Buckley
Written by Warren Buckley

Some things will look and work the same, while other things will change - for the better”. We’ve said that before - but what will actually change? What do you need to be aware of, look forward to, and what will this mean for your future Umbraco projects? We get it - it’s nice to be prepared. That’s why we’ve gathered a top 5 of the biggest changes and improvements you’ll see going from working in Umbraco 8 to Umbraco 9 as a developer: 

What's Umbraco 9? 

Umbraco 9 is the upcoming new major version of the open-source Umbraco CMS. This version is a migration of the entire Umbraco codebase from ASP.NET to ASP.NET Core (and .NET 5). The release date for Umbraco 9 is September 28th, 2021.
Learn more about the Umbraco 9 project right here.

The top 5 changes you’ll notice in Umbraco 9 (and why this is cool)

1. The super obvious one - the new framework. 

The change from .NET Framework over to .NET Core/.NET 5 is the obvious and biggest change. Microsoft is no longer working on the older technology of .NET Framework. So an upgrade was necessary and the Umbraco development team together with the Unicore community team has brought the codebase up-to-date and in doing so will help make Umbraco attractive to new C# and .NET developers - and make the CMS more future-proof. With moving the entire codebase to .NET Core we gain performance increases due to a better underlying technology stack but I think the most common thing people associate with .NET Core is the addition of cross-platform compatibility. Yep, that's right, you can finally make some of your colleagues running on a Mac a lot happier as they can run Umbraco natively on their machine without the use of a windows virtual machine in order to do development work on an Umbraco site 🥰 

Access to ASP.NET Core 5 tech

A big benefit to upgrading to this new framework is that you now get access to new technology in your Umbraco 9 projects:

Razor TagHelpers

This is an alternative approach to HTMLHelpers in Razor which allows you to add your own HTML attributes or HTML tags that can be processed by C# code before the raw HTML output is sent back from the server. 

Microsoft has some great documentation on this if you want to investigate further:

Dependency Injection

Microsoft .NET Core has allowed us to use Microsoft’s DI container for Umbraco’s core code. You have the same possibilities to inject what you need into your own classes and code as required. This means that you are now able to inject services directly into your Razor views with the @inject keyword. Pretty neat. 

Take a look at the documentation from Microsoft below for more in-depth details: 

View Components

This is a new concept in .NET Core that allows us to have a more powerful approach to Partial Views where you no longer need to have a controller with ChildActions in them.

Take a look at the documentation from Microsoft:

As well as this great community article from Dennis Adolfie in Skrift:

2. Updated Dependencies

For Umbraco to run on .NET 5, we needed to ensure our external dependencies would also support it, so we’ve updated to newer versions or switched to projects that offer support for the new tech stack.

Client Dependency Framework is now Smidge 

CDF handles asset bundling and minification inside the backoffice of the CMS. Optionally, if you want to use it in your frontend code, this is now possible thanks to a new project called Smidge by Shannon Deminick that does the same thing as CDF. 

I recommend you take a look at the GitHub project documentation if you are curious about what has changed there.

ImageProcessor is now ImageSharp 

This project from community member James South has also a new and updated project called ImageSharp that now works cross-platform allowing Umbraco to help you create the media crops and resizes you need for your website on umbraco 9. Thanks, James 


This project from Shannon Deminick, is the tool that handles indexing and gives extensive search capabilities to your Umbraco website. Under the hood of Examine, it uses a technology called Lucene.NET and this has been updated to a newer version, compatible with .NET 5 and Umbraco 9. 

3. Configuration

This is a big topic that has seen a lot of changes in Umbraco 9 due to .NET Core changing how it handles configuration. This change is probably the biggest to understand, however, this change is good and opens up to a lot of flexibility and different options, such as allowing configuration to come from various different sources be it AppSettings.json and the equivalent environment-specific overrides AppSettings.Development.json, along with them coming from environment variables used in places like Azure.

I recommend taking a look at my video to help you understand what has changed, along with a few other recommended posts to read:

With Umbraco Health Checks in the backoffice, it was previously possible to update some configuration automatically for you. With configuration changed in Umbraco 9 and it being read only, the health checks will now only prompt you on what settings and values you need to change it to.

4. Events

This has changed to use notifications as opposed to static events and has been heavily inspired by the MediatR project.

This is cool because notifications are handled by the Dependency Injection container and are not tightly coupled to the specific implementations anymore. Furthermore, we now support async notifications.

With this big change, my awesome bunch of colleagues has already got onto documenting this new approach and have examples to follow along with.

Alternatively, if you like the more “show and tell” approach, I’ve created a video that will show you how to work with the new pattern: Migrating Event Handlers to Notification Handlers in Umbraco V9

5. Packages

This is another area where we have had to change a few things. Now, packages have to be installed via Nuget. We have had to change the approach on how we install packages due to how .NET Core works where we can not populate the IOC container at runtime and restart the application like we have done in Umbraco 8 with the package.zips.

So the option to install packages via the Umbraco backoffice with a simple click is no longer an option, however, an upside to this is that we now have implemented package migrations which allow you to run custom code and migration code when your package is installed or upgraded. You can learn more about the new package approach in Umbraco 9 in the “Packages in Umbraco 9 via NuGet” blog post.

All Umbraco HQ packages (Forms and Deploy) are ready for Umbraco 9 and we’re pleased to see that many of the external Umbraco packages are also ready for the Umbraco 9 release (H5YR!).

Bonus tip!

If you want to dive a bit deeper into the new changes in Umbraco 9, and want to get a more visual recap of them, I suggest watching the great Codegarden talk by Umbraco 9 team lead Bjarke Berg and developer Elitsa Marinovska “Umbraco 9 - The next major version” 👇

Any changes for content editors in Umbraco 9? 

Most of these changes are closer to the metal and under the hood, so your editors will still have the same Umbraco experience they know and love today with Umbraco 8.

All the editor-friendly features and fixes you know from Umbraco 8 - including the new ones e.g. tabs -  will be available in Umbraco 9. So the Umbraco user experience is, at its core, the same and should be instantly familiar for content editors.

And then there’ll of course be more features to come! With Umbraco 9 being the new major version of Umbraco, this is the version you can expect new editor-friendly features on. 

Umbraco 9 training courses

With the new changes and improvements mentioned above, it’s only natural to ask how you can upgrade your skills and certification to Umbraco 9. 

All our certification courses will be updated to Umbraco 9 and starting 2022, you’ll get taught Umbraco in version 9 when you go on an official Umbraco training course. 

Should you wait to get certified? No need - if you buy training today, you’ll automatically get free access to the related Umbraco 8 to 9 bridging courses which will elevate your skills and certification to Umbraco 9. This goes for the following four courses:

  • Umbraco, MVC, and Visual Studio 
  • Umbraco Application Integration 
  • Security in Umbraco 
  • Umbraco Load Balancing

The four bridging courses will be available from 2022. 

If you currently hold an Umbraco 8 certification based on one of the four courses above, you’ll get the opportunity to elevate your skills by purchasing and completing the bridging courses when they become available in 2022. 

Learn all about the bridging courses and the new certification structure starting 2022 in the “Future certifications in Umbraco” blog post. 

Join us for the live launch stream

On September 28th, 2021 at 14:30 CEST (check when this is in your timezone), we’ll be launching Umbraco 9 🎉
This huge release calls for some extra celebration and we’ve therefore prepared a special Umbraco launch show - and you’re invited!

Sign up for the free live launch 

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