A Strategic Guide: How to Responsibly Select Your Modernization Provider
A new market regulatory recommendation (e.g. DORA or NIS2 recently). Executive pressure for faster product rollout. Another audit highlighting the same technological risks. Sound familiar? Modernizing the core system is no longer a choice but a condition for survival in the market. The problem is that choosing the wrong partner for this operation is worse than inaction – it’s a straight path to operational catastrophe. This article is not another piece of praise for automation. This is a set of hard criteria that will allow you to distinguish true experts from salespeople before you make a company-critical project decision.
Among the four common approaches—Rehost (move without changing what’s inside), Replatform (update the runtime/platform with small tweaks), Refactor (tidy up the internals while preserving how the business works today), and Rebuild (start from scratch) — Refactor is often the most balanced path. The goal isn’t a hand-written functional analysis; the goal is to faithfully carry over current behavior using automation, so you can improve the foundations and move faster afterward.
That leads to a practical conclusion: the best way forward is usually a specialized external provider. Modernizing mission-critical systems is a distinct craft—short in calendar time, but demanding in method, automation, and a calm, predictable cutover. Building this capability in-house for a one-off project rarely pays off. The hard part is choosing the right partner. Many of us have been on your side of the table: defending budgets, owning continuity, and trying to trust a new supplier. We know it’s hard, and we’ve learned what actually reduces risk and uncertainty.
Trust has to be built with a new provider. Don’t let smooth talk, pretty slides, or easy agreement sway you—those prove sales skills, not delivery. Trust grows when the team in front of you can show how they deliver, how they measure success, and how they handle rough edges without drama. Below are seven criteria that make that visible and verifiable.
7 KEY CRITERIA FOR RISK MANAGEMENT
1. EXPERIENCE IN HIGH-AVAILABILITY TRANSACTIONAL SYSTEMS Modernization is work on a living system. Ask how they plan changes without stopping day-to-day operations, how they watch the system during a switchover, and how they cooperate with ops. The point isn’t to dissect your system function by function; in a refactor, automation should read existing artifacts and carry behavior across with discipline.
2. A SWITCHOVER SCENARIO THAT YOUR SECURITY DEPARTMENT WILL ACCEPT The CIO isn’t thinking about „continuity”; they are thinking: „What happens if my customers’ transactions disappear during the switchover?” Ask the potential partner not WHETHER they will ensure continuity, but HOW they intend to do it. Demand a precise action plan: How long will both systems run in parallel? How will you automatically verify 100% transaction consistency between the old and new system? Who and based on what data will make the final cutover decision? If the answer is vague, it’s a red flag.
3. CLEAR, REHEARSED ROLLBACK Plan B gives courage to Plan A. Ask for the concrete steps to revert, the decision owner, expected duration, and impact on users and data. Ideally, they can show where these procedures were prepared and—when needed—used.
4. YEARS OF PRACTICE AND BUSINESS STABILITY Look for several years of doing this kind of work. Ask about scale, duration, hard moments, and lessons learned. Check team stability: will the people you meet finish the job and stay through hypercare?
5. GUARANTEE OF 100% BUSINESS LOGIC PRESERVATION Over the years, dependencies have accumulated in your system that no one controls today. Manual tests may not catch this. Therefore, ask what tools the partner has to automatically compare the operation of every function before and after migration. A true expert won’t say, 'trust us,’ but will show you a mature, ready-made testing environment that provides mathematical certainty that 1+1 in the old system is still 2 in the new one.
6. SECURITY COMPLIANT WITH INDUSTRY AND DORA STANDARDS Who can access data, on what terms? How are changes recorded and risks reviewed? Good providers work to documented standards (ideally externally confirmed), so critical steps don’t depend on goodwill. This isn’t bureaucracy; it’s repeatability.
7. CONTEMPORARY, PROVEN, EVOLVING TOOLING—AND A CLEAR ‘WHAT’S NEXT’ Automation of analysis, component transfer, and result comparison should be the heart of the method. Ask what tools they use and what you keep afterward: documentation, scripts, tests, deployment mechanisms, and monitoring. Also ask about their ongoing R&D and how they’ll leave you ready to evolve faster on your own—the first weeks post-go-live, the handover plan, and the path for future changes.
CASE STUDY: How a European Stock Exchange Modernized Its Core Indexing System in 6 Months—With Zero Downtime
Context and Challenge: A European Stock Exchange relied on a critical system built on obsolete technology, responsible for calculating and distributing market indices. This system demanded immediate modernization due to rising operational risk. The key challenge was to execute the migration in record time, guaranteeing 100% result consistency (parity) and absolutely zero operational downtime, as any error or interruption would lead to financial catastrophe.
Method and Execution: Instead of a costly and risky ground-up rewrite, we implemented a highly automated refactoring process. The new system was launched and run parallel to the old one, maintaining dual-run verification for several weeks. Our automated tools continuously compared the index calculation results before and after the migration, ensuring the mathematical certainty of identical business outcomes. The final cutover was executed during a single, strictly planned weekend, resulting in zero impact on Monday’s market opening. The project was completed on schedule in just 6 months.
Results and Lessons: The client gained a modern, Java-based tech stack, significant improvements in stability and system response times. Logical fidelity was fully maintained, and the internal IT team was completely empowered with tools for independent future development.
Lessons Learned for the Next Team:
- The 100% Parity Rule: In zero-downtime environments, automated parallel result comparison is the only method of verification that provides absolute certainty.
- Team Empowerment: Logic preservation is maximized when the client’s internal team (those who know the original PL/SQL) becomes the primary owner of the new Java code post-migration.
- Engineering Precision: Achieving such rapid deployment (6 months) was only possible due to 100% automated refactoring, which reliably eliminates the risk of human error.
CONCLUSION: It’s About Risk Management, Not Technology
Choosing a migration partner is one of the most critical decisions a CIO can make. The landscape is littered with failed projects that were derailed by partners who underestimated complexity or over-sold their capabilities.
By using these seven criteria, you shift the conversation from features and pricing to risk and certainty. The right partner doesn’t sell you a technology; they deliver a predictable, safe, and successful outcome that strengthens the business and solidifies your position as a strategic leader.