Legacy Application Modernization: Inch-By-Inch Guide On How To Make It Right

When your software does not meet challenges of time, it might be wise to consider legacy application modernization. But here’s the kicker: these initiatives are only successful in 26% of cases. No wonder many business owners cling to the idea of “why fix what’s not completely broken”, delaying necessary upgrades until it’s almost too late.   

Bad news: this mindset won’t cut it anymore. Why? Well, what should we start with? Sluggish performance and glaring security vulnerabilities are just the beginning. Legacy systems drain resources with high maintenance costs and struggle to scale with your growing business.

Fifteen or twenty years ago, you could have used software for up to eight years stress-free. Today, the lifespan of tools and frameworks has halved, forcing companies to go through the cycles of modernizing their apps every four years. 

— Dzmitry Shchyhlinski, Lead Solution Architect, *instinctools

Good news: we know how to get software back on the right track before it goes south. In this article, *instinctools’ very own head of backend development and lead solution architect will walk you through all of the stages of the modernization journey and legacy system modernization approaches, providing a slew of real-life examples along the way. 

What makes a legacy app?

Our vision of a legacy app isn’t limited to obsolete technology. At *instinctools, we stick with Gartner’s definition, considering any solution outdated if it relies on software, technology, methodology, or process that has become ineffective while remaining critical to daily operations. 

Nine signs your app is screaming for an upgrade

You know what they say: if it looks like a duck, swims like a duck, and quacks like a duck, it’s probably a duck. The same goes for legacy software: if it looks old, runs slowly, and requires a lot of effort to make any improvements, it’s probably outdated. Anyway, to help you make a well-informed choice we’ve curated a list of some blatant indicators, signaling your app needs a makeover. 

• Skyrocketing infrastructure costs due to an outdated technology stack
• Obsolete UX/UI failing to meet user expectations
• Limited scalability that hinders your growth potential
• Low flexibility, making integration with modern apps impossible
• Poor performance as your app’s daily norm
• Numerous security vulnerabilities and compliance risks
• Inability to find staff with the right skills to support the app
• Code bloat, making maintenance pricey and challenging 

Spotting the apps calling for legacy modernization isn’t a hard nut to crack. Modernization itself, though, might be — given how deeply your software is embedded in your company’s daily operations. 

Legacy app modernization has many faces

Legacy application modernization comes in various forms: 

• Encapsulating provides a gain with no pain when you reuse the existing app’s valuable features with minimal changes by making them accessible for other applications through an API.   
• Rehosting implies keeping the old code and features as they are while redeploying the app component to other infrastructure (on-premise; private, public, or hybrid cloud).
• Replatforming covers elevating the software performance and scalability and reducing operational costs by migrating to a new platform, while preserving the previous code structure and core functionality.
• Refactoring includes optimizing the existing code in line with up-to-date coding standards to eliminate technical debt.
• Rearchitecting entails substantial changes to the application architecture and code by replacing a monolith with microservices or, sometimes, the other way around when the microservices were written at different times by different developers and are easier to maintain if consolidated in a single monolith.
• Rebuilding involves completely rewriting or redesigning software components while keeping the app’s overall scope and specifications. 
• Replacing existing systems with new ones is a last-ditch step required when the end users’ needs have completely changed and, to meet them, none of the current app’s components and layers can be reused. 

As you can see, there’s no need to burn your boats, when you can sail smoothly into massive improvements with time-saving, budget-friendly modernization strategies. If identifying the right one feels overwhelming, legacy application modernization services from a trusted software development company provide expert guidance. 

Risk it for the biscuit: measured rewards of legacy modernization

The prospect of IT legacy modernization can look intimidating, but the rewards are well worth the effort. Here’s how transforming your software can benefit you in multiple ways: 

• Maintenance cost. Aligning your app with current code practices, architecture, design, etc., allows you to trim down the cost of software upkeep by at least 30%*.
• Quality. Reducing the amount of flawed code in production to less than 1%* sounds valuable, isn’t it? 
• Speed. Releasing new features up to x50* faster can put you ahead of the pack.
• Regeneration. Minimizing the downtime with the average mean time to recover (MTTR) of just 2–10 minutes* raises the app’s reliability.
• Integration. Zero drawbacks when integrating your app with other solutions contribute to the hitch-free functioning of your software ecosystem.

*Based on our client’s legacy modernization projects 

The nuts and bolts of the legacy application modernization process: 7 steps to follow

Despite the complexities and peculiarities of software modernization initiatives, there are guaranteed strategies you can follow to tackle legacy modernization challenges head-on.

1. Run an assessment to define the problem areas

The measure-twice-cut-once principle is also valid for legacy modernization.

A clear understanding of your business drivers and an in-depth investigation of software problem areas enable you to set the right priorities for app modernization and strategize future growth.

Revamping a legacy app should start with a thorough assessment that covers all the bases: 

• Project documentation. Outdated software often lacks solid documentation. Catalog all the data on the app to identify any missing mandatory documents.
• Technology analysis. Evaluate your current tech stack, and choose the most suitable programming languages, tools, frameworks, integrations, based on the available tech expertise and trends, shaping the landscape in your industry.
• Architecture audit. Examine the systems’ architecture design, consistency, and quality against industry standards to get an idea of what can be done to achieve seamless scalability, high integration capabilities, and glitch-free maintenance.
• Code review. Is your source code up to snuff? Compare it against the present-day coding best practices to spot and weed out any spaghetti code.
• Data quality estimation. Inspect the app’s data layer for consistency, accuracy, and completeness to ensure no junk data sneaks into your updated software database. 
• UI/UX evaluation. How user-friendly is your app? Analyze overall usability, ease of navigation, element layout, and visual design to identify the areas that need a facelift.
• Performance testing. Put your app through its paces. Check the app’s stability, scalability, speed, and responsiveness under various workloads to uncover performance bottlenecks.

Prioritizing the assessment stage upfront is your secret weapon against future headaches. If your project vision is blurry or stakeholders aren’t on the same page, consider a discovery workshop. This helps synchronize your modernization strategy with your business context and user demands. 

If you don’t have the capacity or specific experts on board to tackle modernization without affecting your ongoing projects, find a tech partner who can steer the ship and bring you to the next destination of your legacy system modernization journey.

2. Identify the relevant modernization approach and technique

After assessing the existing legacy system, you can chart the right course and choose which of the legacy system modernization approaches works best for you. 

In general, there are two main options for a legacy system transformation —  the big-bang (revolutionary) method and the band-aid (evolutionary) one. Truth be told, business owners tend to choose risk-prone gradual improvements over cliff-jump actions.  

There’s only one situation when you have to put everything on the line and follow the big-bang approach. When major security issues or compliance violations arise, you don’t have the luxury of taking it slow. It’s either go big or go home. You have to act now to avoid losing customers and facing massive fines. 

— Dzmitry Shchyhlinski, Head of Backend Development and Solution Architect, *instinctools

We’ve put together a comparison chart to help you weigh the pros and cons of each modernization technique we’ve mentioned earlier, in terms of cost, time, complexity, and risk.

Technique	Cost	Time	Complexity	Risk
Encapsulating	The lowest	The quickest	The lowest	The lowest
Rehosting	Low	Medium	Low	Medium
Replatforming	Medium	Medium	Medium	Medium
Refactoring	Medium	Medium	Medium	High
Rearchitecting	High	Long	High	High
Rebuilding	High	Medium	High	High
Replacing	The highest	The longest	The highest	The highest

An iterative approach lets you mix and match two or more techniques to achieve the highest value for your business. For example, one of our clients, a provider of SaaS personalization engines, started the modernization process with code refactoring of their flagship software and then decided to proceed with the redesign. That way, they were able to move toward simplified product maintenance and design consistency across all of their current solutions. 

3. Update your Vision & Scope and create a roadmap

The reason why 74% of modernization initiatives fail is mismatched project visions among stakeholders. Consistent, well-organized documentation keeps everyone aligned and on track. 

First of all, make sure the app’s vision and scope reflects the latest end-user needs, compliance, and security requirements. 

Second, you should put a premium on creating a project roadmap with the goals and objectives of your legacy system modernization, key project deliverables, business risks, success criteria, a timeline with milestones, and a team lineup. 

4. Set up app modernization team

Planning is vital, but you’ll need the doers to pull off your legacy app modernization. 

An all-embracing roadmap, outlining mandatory roles within the team and the number of FTEs, enables you to allocate your resources wisely when arranging a team for a legacy system modernization. 

However, it’s not carved in stone, and your initial goals may evolve, requiring team decomposition or expansion.

Take, for instance, a SaaS LMS provider that partnered with *instinctools. Initially, they sought our solution architects to rearchitect their current educational platform. However, amid our cooperation, they decided to strengthen their internal team with our senior frontend developers, aiming for a complete system redesign.  

5. Execute modernization

At this point, actions you take will hinge on the specifics of your modernization project. For example, redesigning involves prototyping, wireframing, and usability testing, while rehosting requires data and storage migration and database rehosting. 

The common best practice for any modernization technique is moving in small iterations so that you can spot and address any risks in the bud and avoid divergence of vision among team members and stakeholders. 

6. Invest in end-user training

Present-day tools and frameworks, modern platforms, revamped architecture, and top-notch design mean nothing without user support. While consumer demands often drive updates to customer-facing apps, internal technology changes tend to neglect employee feedback. 

How to prevent staff resistance to your modernization efforts? We suggest initiating user training before rolling out the renovated app to familiarize your employees with the new system. For significant software changes or complete replacements, consider implementing a digital adoption platform (DAP) for contextual in-app guidance. 

7. Support and optimize

Ensuring your renewed system runs flawlessly requires continuous proactive monitoring. Regular tech, UX/UI, and performance audits, code reviews, and data quality and security checks before, during, and after modernizing legacy systems increase the odds of their smooth operation. 

It’s time to act

Staying stuck with dust-covered software infrastructure, design, and legacy code means losing out to more agile and innovative competitors. But there’s a way forward through modernizing legacy systems in a well-thought-out, calibrated manner. 

And that’s where we come in. Instinctools is your tech partner for every step of the modernization process. We focus on maximizing what works and fixing the trouble spots, ensuring your app is sturdy and cost-effective.