The modernization of legacy systems is no longer a "desirable" agenda and has become a strategic imperative. In 2025, most companies still relied on legacy applications for critical processes, C-level executives were already prioritizing modernization initiatives to sustain competitiveness, security, and scale.

What's at stake

Systems designed in another technological context carry limitations in integration, scalability, and security, holding back the adoption of cloud, microservices, real-time data, and AI, which have already become pillars of efficiency and digital innovation.

In addition to the brake on innovation, the cost of maintaining old technologies tends to grow due to a shortage of talent, low automation, and high sustainment effort. Studies show that maintaining legacies can become significantly more expensive than adopting modern architectures over time. 

Key challenges

1. Complexity and interdependencies
   Monoliths with decades of integrations create a risk of regression and long cycles of change, which makes any functional evolution more expensive and slows down.
2. High maintenance cost
   Obsolete technologies require rare specialists, legacy tools, and manual processes, putting pressure on IT OPEX. 
3. Limited integration and scalability
   Difficulty in exposing APIs, operating events, elastically scaling, and consuming cloud-native services directly impacts time-to-market.
4. Security and compliance risk
   Longpatching cycles, unsupported dependencies, and poor observability extend the attack surface and audit effort (e.g., Data Protection Act).
5. Distributed data and knowledge
   Complex migrations and lack of documentation increase the risk of unavailability and knowledge loss.

Tangible benefits of modernization

• Performance and efficiency: Modernized applications process faster, sustain higher loads, and reduce operational bottlenecks.
• Cost reduction: cloud migration, pipeline automation, and selective refactoring reduce infrastructure and support expenses.
• Security and compliance: Continuous updates, modern identity, and observability elevate security posture and facilitate audits.
• Openness to innovation: Enables AI, analytics, microservices, and API, which are the foundation for new digital products and experiences.

When it's time to act

Classic triggers include: misalignment with business needs, rising maintenance cost, operational risk of downtime, poor user experience, and barriers to integrating new capabilities.

Avoid "all or nothing"

There is no single path. Design depends on obsolescence, business impact, risk, and budget. Among the most common approaches:

• Rehost / Replatform / Refactor for cloud (start with what pays fast, evolve to native optimizations).
• Containerization and orchestration (Docker/Kubernetes) to standardize build/run cycles  and reduce couplings.
• Modular refactoring/microservices to isolate critical domains and accelerate change.
• Selective rebuild of components with higher technical output or  monolith strangler fig pattern.
• Replace when the legacy does not offer technical/economic feasibility of evolution.

Governance, risk and compliance "by design"

Embed security and compliance from the first commit: modern identity, secrets management, policy as code, quality gate conveyors, SAST/DAST, and audit trails. In addition to reducing exposure to incidents, this simplifies regulatory adherence and compliance with market audits.

People and culture: the decisive factor

Strategies fail not only because of technology, but because of resistance to change, skills gaps, and lack of communication. Treat modernization as a transformation program, with continuous enablement, change management, and clear governance between IT and the business. 

Modernize to compete with security, speed, and clarity

The modernization of digital platforms is the way to reduce costs, accelerate deliveries, strengthen security, and unleash the innovation that the business needs, now. The data is unequivocal: most companies still rely on legacy and already recognize modernization as a priority, precisely because the benefits far outweigh the challenges when the movement is value-driven and executed incrementally.

How act digital can help

At act digital, we connect strategy, architecture, and execution to modernize with minimal friction and maximum impact:

• Technical-functional assessment and business case (cost, risk, ROI);
• Cloud-ready architecture (APIs, events, observability);
• Pipelines CI/CD, SRE e security by design;
• Roadmap for incremental refactoring and change management.
  

Ready to take the next step?

Talk to our experts and turn your legacy into a competitive advantage.