paying down tech debt: a CIO’s guide to working with legacy code.

Ideally, all software projects would have a tidy modular structure. This would make it easier for tech leaders to plan upgrades, manage integrations and ensure unbreakable cybersecurity.

But, as all CIOs know, we don’t live in an ideal world. Every organization has what might be considered legacy code, and dealing with it requires a smart, high-level strategy.

what counts as legacy code?

Legacy code is any software that creates a tech debt, an above-expected need to develop and maintain that software.

Tech debt usually arises when developers opt for a fast-and-dirty solution. While this might help hit a deadline in the present, it creates a future obligation to improve on that original work.

In this sense, legacy code is any software with features such as:

• monolithic structure
• poor support for integration
• structural issues that impact performance or security
• insufficient documentation
• no automated testing
• reliance on obsolete technology

Note that age is not a factor here. Old software isn’t a problem if it’s stable and supports your broader tech strategy. Conversely, a recent software project might be considered legacy if it creates an ongoing tech debt.

how to work with legacy code

It’s helpful to have a high-level plan for dealing with weak legacy code. Here are five steps to help you manage legacy software and avoid issues with tech debt.

1. identify

The first step is to identify what you mean by “legacy code.” It includes anything that fails to meet general expectations, such as benchmarks for stability and performance or your standards for documentation. It can also include anything that doesn’t fit within your current strategy or systems architecture.

Next, your team can work through the current codebase and identify any significant issues. They can also measure the severity of each issue (from mild to severe) and assess the potential impact of not addressing the issue.

2. document

After this, knowing how the legacy code impacts your tech stack is essential. Get your team to map out all known integrations and dependencies so that you can fully understand the impacts of change.

Talk to end users and learn more about their processes. You need to understand how any tech changes might impact day-to-day operations. But you can’t learn this from the code itself — you must discuss it with stakeholders.

3. maintain

Maintenance is the most urgent responsibility when dealing with legacy code. Your team needs a plan to ensure everyone understands weak code issues. Teams may also need to review and update relevant documentation.

Maintaining legacy code often involves more than just understanding its complexities. It's about actively managing its impact on your current systems. To mitigate issues effectively, prioritize refactoring critical sections that pose the most significant risks or bottlenecks and introduce intelligent automation for key functionalities to ensure stability during updates.

4. update or replace

The long-term goal should be to eliminate legacy code. This may involve launching a new project initiative to rewrite the weak code, or you might look at a complete replacement with something new.

Start with a comprehensive evaluation to distinguish between code that needs updating for compatibility and efficiency versus code that should be replaced entirely due to obsolescence or security vulnerabilities. Prioritize updates that offer the most significant improvements in performance and security, and consider the adoption of new technologies that align with your strategic goals. For replacement, select solutions that address current needs and offer flexibility for future expansion and integration, ensuring a resilient and scalable IT infrastructure.

5. prevent

Legacy code is often a cultural problem rather than a technical issue. It’s the result of understaffed projects, unrealistic expectations or poor communication. The result is software that doesn’t meet your desired standards, plus a tech debt that must be repaid.

Preventing legacy code and its associated tech debt starts with nurturing a culture that values learning and adaptability. Make it a habit for your teams to embrace best coding practices early on. This includes simple yet effective steps like code reviews, pair programming and sticking to coding standards that encourage clean, modular and easily testable code. Also, promote continuous training and development to keep everyone sharp and up-to-date with the latest tech and approaches. By doing this, you're not just dodging legacy code. You're aligning your development efforts with your long-term goals, paving the way for an IT setup that's both agile and robust.