When is it time to upgrade to Mule 4?

Picture this: you’re buying a new car. Should you upgrade your vehicle to get better features? Usually, you’re buying a vehicle to drive it — but, thanks to technology, there are dozens of other reasons to upgrade. Your current ride probably doesn’t have the latest safety and convenience features, and your warranty has likely expired. So, should you hang on to your old wheels? Think about cost, safety, and connectivity. If your mechanic is spending more time with your car than you do, it’s probably time to trade up.

Compare that to a software upgrade. Today, we see technology advancements develop faster than ever before and we are expected to keep up. It is not as simple as developing new systems through advanced infrastructure. Soon, these systems become outdated and difficult to support. Even software security experts don’t upgrade their software immediately when a new version comes out. Software upgrades need to be planned carefully. 

Projects to upgrade software platforms can be challenging to sell to the leadership team because it is difficult to show what the value of the investment is. Many IT managers and project leaders use the threat of an end to vendor support to sell upgrades, but system maintenance is often the primary reason.

As your teams become experts in Mule, management is less likely to buy into the myth of a lack of vendor support. Therefore, IT managers must defend the upgrade with a compelling business case. In our experience, companies have said that the approval process took longer than the upgrade itself. Developing a plan to determine how the upgrade will affect the enterprise is the most crucial part of the upgrade project and the reason it takes the longest. When building a business case for Mule 4 upgrade, remember that although you can reduce costs, the benefit of additional functionality can far exceed this. 

In this blog, I will discuss strategies for planning a Mule 4 upgrade and when it is time to do so.

Why should I upgrade?

The best stability and software performance is achieved with regular and planned software upgrades. Often, bugs will be fixed and new features will be added. Mule 4.x has been updated primarily for ease of use: with improved performance and autonomous capabilities. The upgrades in Mule 4 offer straightforward usability and allow the users to learn the product quickly and efficiently. 

Here are some reasons why you should upgrade to Mule 4.

  • Easier to work with properties and to provide consistency across connectors.
  • DataWeave replaces MEL as the default. It’s simple syntax makes it easier to learn.
  • Mule 3 transports were replaced with new operation-oriented connectors that are easier to use.
  • Easier and more powerful error handling with a new Try scope
  • Mule 4 automatically handles data streams for users that greatly simplifies working with data in Mule runtime engine.
  • Studio 7 features a simplified palette, improved Maven integration, and many other usability improvements.
  • The internal execution engine has been updated with a new self-tuning and non-blocking reactive engine. 

How should I plan for the upgrade?

Although software upgrades can be simple and straightforward, a successful transition requires thorough planning and close consideration of the potential impact on the rest of your technology environment. Moving from Mule 3 to Mule 4 is not merely an upgrade, it’s a rewrite of your APIs and applications. 

Doing a lift and shift of Mule 3 applications to Mule 4 is not recommended as it adds no business value. In general, the recommendation is to develop the net new APIs and applications in Mule 4, and look for an opportunity to migrate the existing projects. When you start planning for the upgrade, follow these steps:

  • Get your teams trained on Mule 4.
  • Have your teams review the Mule 4 documentation.
  • Ensure you have the proper deployment environment. Perform environment sizing to ensure you have enough capacity to run Mule 3 and Mule 4 applications.
  • Start with building out common framework assets such as:
    • Templates
    • Loggers
    • Exception-handling routines
    • Policies
  • Build out your new CI/CD pipeline. 
  • Educate your internal organization around all of the above.

Once you plan the upgrade, it is important to execute it without prolonging it. Otherwise, it will end up like the project of “painting the forth bridge.” 

What options do I have?

Whether you are a new Mule customer who is getting started on Mule 4 or an existing Mule 3 customer, here are some options for you to adopt Mule 4.

  • Net-new projects:
    • Complete the Mule 4 training course and obtain Mule 4 certification.
    • Get familiarized with Mule 4 platform and Studio 7 by doing some pilot projects.
    • Develop new applications on Mule 4.
  • Existing Mule 3.x  applications:
    • We recommend upgrading to the latest of Mule 3.9.x and staying on it as long as possible (support extended until March 2024).
    • There is no urgency and in some cases little benefit from doing lift and shift of Mule 3 applications to Mule 4.
    • Review and prioritize existing Mule 3 applications for Mule 4 adoption. Plan for a phased Mule 4 migration. Group and prioritize existing Mule 3 applications. 
  • When a change or enhancement in functionality is required:
    • If any change is required to the existing Mule 3 applications, re-develop the applications on Mule 4 to take advantage of new features.
      • Estimated effort is 40-60% of original development time per application.
  • When there is no change required for an application:
    • Leave these applications on Mule 3 until there is a change.
    • Have a periodic check to assess the timing of the upgrade.
    • Review all applications still on Mule 3 as of January 2023:
      • Budget and plan for the upgrade.
      • Complete redevelopment on Mule 4 by December 2023 the latest.
  • Deployment options: 
    • It is not recommended to run Mule 3 and Mule 4 on the same hardware. 
    • If you are a CloudHub customer, you can deploy Mule 4 applications to the workers as CloudHub provides application isolation.
    • If you are an on-prem/hybrid customer, you can add on-prem Mule 4 servers alongside 3.x servers. 
    • Setup Runtime Fabric and deploy Mule 4 apps.

What are my steps?

After learning about the upgrade process and the options, it is equally important to know what the execution looks like. From our experience working with customers on the upgrade, here is a list of high-level steps to help you with the upgrade:

  1. Add all required modules, such as the Database connector, to Anypoint Studio 7 palette.
    • You can add modules through Studio 7 palette. Other modules are available in Anypoint Exchange.
    • All Mule projects are Mavenized by default when you add the modules to your project.
  2. Migrate all the global configurations.
  3. Migrate configuration properties.
  4. Understand how changes to the Mule message structure (attributes, payload, and variables) affect your configurations. 
  5. Update your expressions and scripts to DataWeave version 2:
    • Be aware of changes between DataWeave 1 and DataWeave 2.
    • Change MEL expressions to DataWeave 2. 
  6. Update all exception handling to Mule 4 with the new exception types that are available.

What training is available?

When adopting or creating new software, training helps users adapt to changes in their functions, while support helps end-users address issues they experience. No matter how user-friendly or intuitive a software is, training is still required for an organization to realize the technology’s full capabilities. I have put together a list of training courses to help your team gain knowledge in Mule 4:

To learn more on Mule 4, check out one of our MuleSoft Training and Certification courses listed above.



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One Response to “When is it time to upgrade to Mule 4?”

  1. This was a very helpful article, as we look to migrate from 3.8.x to 4. The steps listed along with the resources are a good go-to guide.