When legacy systems become evidence: how to preserve, analyze, and present old code in litigation

The software industry moves at lightning speed. It’s easy to forget how much critical software still runs on outdated systems. But when litigation arises—especially in matters involving trade secret misappropriation, breach of contract, or intellectual property infringement—these legacy systems often become the key evidence that can make or break a case.

Whether you're dealing with decades-old source code, unsupported programming languages, or obsolete hardware, navigating the legal and technical demands of legacy system analysis requires a unique blend of forensic expertise, software knowledge, and litigation experience.

At Eureka Software, we specialize in helping law firms and businesses extract value from legacy evidence. In this blog, we’ll walk through how to preserve, analyze, and present old code and systems effectively in court, while avoiding the pitfalls that could compromise your case.

Why Legacy Code Still Matters in Court

You might assume that once code is outdated, it’s irrelevant. But in litigation, what was built, when, and how matters a great deal.

Legacy systems may hold the key to:

Proving authorship or ownership in IP disputes

Establishing timelines for invention or development

Demonstrating trade secret use or access

Tracing functionality relevant to breach of contract claims

Defending against infringement claims by showing prior art or independent development

Unfortunately, because legacy systems are often undocumented or maintained by people no longer with the company, extracting that information is anything but simple.

Step 1: Preserving Legacy Evidence

Before anything else, proper preservation is essential. Mishandling old systems or failing to document their state can lead to data loss, spoliation claims, or inadmissible evidence.

Establish Chain of Custody

Just like any other form of digital evidence, legacy code and systems must follow a clear and documented chain of custody. This ensures:

The code hasn't been altered

Access is limited and logged

Evidence is admissible in court

At Eureka Software, we use industry-standard protocols to preserve digital assets in forensically sound environments, including air-gapped systems when needed.

Make a Forensic Copy

Before analysis begins, create a bit-for-bit forensic image of any relevant files, drives, or repositories. This allows analysts to work from a copy, protecting the original data.

Identify Relevant Artifacts

Legacy systems may contain:

Source code

Compiled executables

Build logs

Email communications

Configuration files

Access logs

Backups or version control (if available)

Gathering all these materials upfront increases the likelihood of a successful analysis later.

Step 2: Analyzing Old Code and Systems

Once preserved, legacy systems must be carefully examined—but this step can pose serious technical challenges.

Obsolete Languages and Frameworks

From COBOL and Delphi to outdated C++ compilers, legacy code often relies on tools that are no longer supported. Eureka’s team brings deep experience across multiple generations of platforms, enabling us to read, understand, and run even the most outdated codebases.

Missing Documentation

If documentation is missing (as it often is), we rely on reverse engineering and static code analysis to determine the software's functionality and structure.

Version Gaps and Lost Repositories

Codebases evolve, and critical commits may have been lost or overwritten. Our forensic analysis involves reconstructing development timelines, identifying contributors, and filling in gaps where possible by utilizing metadata, backups, and partial logs.

Custom or Proprietary Platforms

Many legacy systems ran on bespoke hardware or OS environments that no longer exist. In these cases, we recreate virtual environments or emulate the original runtime to reproduce functionality and confirm behavior.

Step 3: Presenting Legacy Code in Court

Technical accuracy is crucial, but it’s only half the battle. In court, complex findings need to be translated into language that attorneys, judges, and juries can understand.

Expert Reports

Our team delivers detailed, well-organized reports that clearly explain:

What the code does

When and how it was created or modified

How it relates to the claims in the case

We separate fact from opinion, making our findings defensible under scrutiny.

Testimony That Resonates

At Eureka Software, our expert witnesses have testified in over 150 cases. We specialize in presenting intricate software details in a way that’s accurate, impartial, and accessible, providing your legal team with the clarity they need to build a compelling case.

Visual Demonstrations

Where appropriate, we use:

Side-by-side comparisons of source code

Flowcharts to illustrate software logic

Timelines showing development milestones or access events

Live or recorded demonstrations of legacy system behavior

These tools help bridge the gap between technical evidence and courtroom persuasion.

Best Practices for Handling Legacy Evidence

If you suspect that legacy code or systems could play a role in a legal matter, here’s what we recommend:

Don’t delay – Time-sensitive systems can deteriorate or become inaccessible.

Secure everything – Preserve not only the code but also context: logs, emails, backups, and documentation.

Call in experts early – The sooner technical experts are involved, the better the chance of preserving and understanding relevant materials.

Avoid assumptions – Just because code is old doesn’t mean it’s irrelevant, or that you understand what it does without proper review.

How Eureka Software Can Help

Eureka Software offers unmatched experience in handling legacy systems and source code in litigation. With over 38 years in software development and expert witness consulting, we:

Preserve fragile digital assets using forensic best practices

Analyze outdated codebases with custom tools and methodologies

Deliver courtroom-ready evidence that stands up under cross-examination

Clarify technical findings for both legal teams and lay audiences

When legacy software becomes a legal asset—or a liability—you need a team that understands both technology and the courtroom.

Need help analyzing legacy code in an ongoing dispute? Contact Eureka Software today to speak with an expert and learn how we can support your litigation team from discovery through testimony.