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Navigating the Modernization of Legacy Applications

When was the last time your laptop or smartphone prompted you to install an update? For most of us, it’s on a daily basis. Why? Because today, technology becomes obsolete at lightning speed. Last year’s functionality can’t keep up with today’s consumer expectations.


By Mike Storey

Why do you need to modernize your legacy application?

While you might be able to put up with an outdated iPhone for a while without too much disruption to your daily life, your business software is a different story.

Let’s say you have a legacy monolithic application (a large, self-contained app combining the full backend and frontend), it’s starting to create some functional challenges for you. As your business needs evolve, you begin introducing new features to the application. There’s no such thing as bug-free code, however, and every new feature introduces the possibility of breaking other parts of the tightly integrated application. As you find and fix the bugs, you also have to incorporate the fix into every other part of your system that interacts with the new feature—often in ways that are not immediately obvious.

This tight integration causes what I like to call “technical cholesterol,” clogging your path to innovation. Technical cholesterol is different from technical debt. Technical debt is primarily driven by external dependencies. Any development effort needs to incorporate reusable code libraries. The use of these external libraries creates dependencies that must be managed, and each library represents a certain amount of work that must be done to keep the application secure and functional. 

You can think of each of those dependencies as having a technical interest rate. The higher your technical interest rate, the more effort will be required to keep the system running. Over time, that technical interest accrues to become technical debt that must be addressed with development effort. In systems with high technical cholesterol and high interest rates, you may find that you have challenges releasing new features even once a year. Even when the updates are delivered, they are more likely to be plagued by defects. In a worst-case scenario you may find that you are introducing defects faster than enhancements.

It’s at this point, when you’re plagued by high costs, impaired growth, and continuous barriers to productivity, that you know it’s time to make a change.

But how? What’s the best way to modernize your legacy system without negatively impacting customers and end-users?

What’s Your Path to Modernization?

Let’s recap: You have a legacy monolithic software application that has accrued unsustainable technical debt and suffers from technical cholesterol caused by tight integrations. It is no longer cost-effective or profitable to maintain your current system, so you’ve decided to modernize. 

At this point, you have reached the first crossroads and you have a decision to make. You can:

  1. Lift and shift the existing monolith into the cloud. With this option, you’ll be keeping your exact same architecture and functionality, but you’ll be moving it to the cloud. This might seem like a workable solution if you don’t want to invest in a whole new architecture, but there are two problems with it. First, the legacy system most likely has dysfunctional issues that need to be fixed. Those problems won’t go away just because you are now in the cloud. Second, this option typically costs more to operate and provides very minimal additional value.
  2. Upgrade to a microservice architecture. In this scenario, you’ll fundamentally restructure the system at an architectural level. Using design thinking, agile devOps practices and cloud native technologies, you’ll build something completely new from the ground up. This gives you the opportunity to solve problems in unique, innovative ways.

Getting to a modern cloud native architecture will more effectively manage technical debt, reduce technical cholesterol, and allow you to innovate by rapidly iterating on new releases. If you decide to upgrade your architecture, you’ll have two more choices:

2a. Upgrade with 100% of current functionality plus a few new things.

If you choose this route, legacy customers won’t have any trouble migrating to the new system, because the new system will operate just the same as the old one. You might add a few new design flourishes, but the essence of  the application and its functionality will remain the same. This is often the course of action in a merger/acquisition scenario. The acquiring company will recreate the software of the acquire, but in a cloud native architecture.

The problem is that you’ll have to absorb costs out of pocket and true innovation will be stifled. Because you’re trying to preserve what’s already there, you’ll miss the opportunity to find new, better ways to solve problems and get work done. It can also be very difficult to justify the expense of a complete rewrite if you are only introducing a few incremental enhancements to the user facing aspects of an application.

2.b. Innovate.

Your other option is to design something fresh and new. Frequently this means that you will build a new MVP and target a market that is adjacent to your existing legacy application (i.e., expanding your market reach and boosting profits). This approach allows you to attract new customers while reimagining your application and is usually much easier to justify financially.

At this point, you may be asking, “But what about my existing customers, they don’t want to give up any functionality. Won’t it be hard for them to migrate to the new system?” That’s a great question and it brings us to our second step in the innovation process.

Here’s where we have some great news for you. Software innovation offers you a golden ticket to continue caring for your current customers while also pursuing a brand new market. Legacy customers can keep the legacy product while you introduce and mature the new product in the new market. Over time as this new application reaches functional parity with the legacy application you can introduce migration tools and consolidate the two sets of customers. 

With this approach you can demonstrate how the new functionality serves your existing customers even better than the old system did. Rather than taking functionality away from your current users, this approach allows them to continue operating with the old system until the new system has reached its full potential. When it’s time for them to transition, they’ll be migrating to a system that meets their needs more effectively and with better functionality than the old system did. 

In the meantime, you have also entered an entirely new market with your product. Win-win.

Why We Recommend Innovation

 At Worthwhile, we recommend taking that last option—innovation—as the best way to adopt cloud native architectures. Using design thinking, we help customers create systems that solve the problems of technical debt and technical cholesterol. This approach allows your development effort to become very agile, introducing new features at a rapid cadence while effectively managing the risks associated with innovation.

Want to Know More? Read This Next.

Your Essential Guide to Cloud Native Software Transformation: How a cloud native architecture manages risks and facilitates high release cadence.

Mike Storey
Mike is the Senior Solutions Architect at Worthwhile and is an advocate for Worthwhile’s Design Thinking practice. With over 30 years in software engineering and IT operations, he has a passion for helping our customers innovate.
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