Modernize legacy software without downtime, chaos, or rewrites
We modernize legacy applications and platforms that run the business. Through structured assessment and phased delivery, we reduce technical debt, improve security and compliance readiness, and make systems easier to change.
Operational challenges in legacy systems we help to overcome
Change becomes expensive, slow, and unpredictable
Over time, even small changes start pulling in hidden dependencies. A single feature touches multiple systems. A local fix breaks something unrelated. Estimates lose credibility, and release cycles stretch from days to weeks. The business loses confidence in its ability to change.
Systems run the business, but no one fully understands them
Critical logic lives in aging code, undocumented rules, and the heads of a few long-tenured engineers. New team members move cautiously. Senior specialists become permanent bottlenecks. The system became fragile with a serious risk of failure.
Technical debt turns into an operating cost
Maintenance work absorbs more effort than new development. Incidents require manual intervention. Outdated frameworks demand rare, expensive skills. Infrastructure costs grow without a clear explanation. What once looked like “just old code” becomes a structural tax on growth.
Data exists, but decisions still rely on intuition
Information is scattered across systems. Reports don’t align. Access depends on who owns which database. Business teams wait for exports instead of acting on insight. The organization has data – but not data it can trust, share, and use consistently.
Security and compliance drift behind reality
Legacy platforms rely on outdated libraries, encryption, and access models. Each audit becomes harder to pass. Temporary exceptions quietly turn permanent. Risk accumulates until regulation, a customer requirement, or an incident forces urgent action.
New initiatives keep colliding with old systems
AI, analytics, new integrations, and additional channels look viable on paper. In practice, legacy constraints slow them down, distort outcomes, or make them too risky to pursue. Innovation can’t be introduced because the foundation can’t support it.
Business outcomes after modernization
From a financial standpoint, modernization matters when it improves predictability, reduces exposure, and makes spending easier to justify and control. The outcomes below describe what changes once systems stop driving unplanned costs and operational risk.
Predictable delivery and planning
Modernized systems reduce delivery volatility. Work estimates become more reliable, release plans stabilize, and timelines stop shifting due to hidden dependencies. This improves forecast accuracy, reduces last-minute reallocations, and lowers the need for emergency funding tied to missed deadlines or urgent fixes.
Lower and more controllable operating costs
As system complexity drops, maintenance effort declines. Fewer incidents require urgent response, overtime, or external support. Dependence on scarce or high-cost specialists decreases. Infrastructure spending becomes easier to attribute, explain, and forecast. More budget can be directed toward planned initiatives instead of unplanned stabilization work.
Reduced operational and financial risk
System behavior becomes more consistent under normal and peak loads. Failures are contained and resolved faster, limiting financial impact from downtime, penalties, or service-level breaches. This lowers the background risk carried on the balance sheet and reduces exposure to cascading operational losses.
Stronger security and compliance control
Security and compliance move into the system itself. Access rules, data handling, and audit trails are defined and traceable. Audit preparation relies less on ad-hoc effort and exception handling, with less interruption to day-to-day work. Regulatory reviews become easier to plan, with clearer scope, cost, and timelines.
More reliable data for financial decisions
Data consistency improves across systems. Financial reporting relies less on reconciliation and manual correction. Management decisions are based on shared, trusted data instead of parallel numbers maintained by different teams. This reduces reporting friction and improves confidence in financial analysis.
Capacity for growth without cost spikes
Modernized systems allow growth and new initiatives without sharp jumps in operating expense or risk exposure. New integrations, channels, or automation can be assessed and introduced without upsetting core operations. Capital can be directed toward opportunities on their economic merit, rather than being shaped by technical constraints.
Predictable delivery and planning
Modernized systems reduce delivery volatility. Work estimates become more reliable, release plans stabilize, and timelines stop shifting due to hidden dependencies. This improves forecast accuracy, reduces last-minute reallocations, and lowers the need for emergency funding tied to missed deadlines or urgent fixes.
Lower operating costs
As system complexity drops, maintenance effort declines. Fewer incidents require urgent response, overtime, or external support. Dependence on scarce or high-cost specialists decreases. Infrastructure spending becomes easier to attribute, explain, and forecast. More budget can be directed toward planned initiatives instead of unplanned stabilization work.
Reduced operational and financial risk
System behavior becomes more consistent under normal and peak loads. Failures are contained and resolved faster, limiting financial impact from downtime, penalties, or service-level breaches. This lowers the background risk carried on the balance sheet and reduces exposure to cascading operational losses.
Stronger security and compliance control
Security and compliance move into the system itself. Access rules, data handling, and audit trails are defined and traceable. Audit preparation relies less on ad-hoc effort and exception handling, with less interruption to day-to-day work. Regulatory reviews become easier to plan, with clearer scope, cost, and timelines.
More reliable data for financial decisions
Data consistency improves across systems. Financial reporting relies less on reconciliation and manual correction. Management decisions are based on shared, trusted data instead of parallel numbers maintained by different teams. This reduces reporting friction and improves confidence in financial analysis.
Capacity for growth without cost spikes
Modernized systems allow growth and new initiatives without sharp jumps in operating expense or risk exposure. New integrations, channels, or automation can be assessed and introduced without upsetting core operations. Capital can be directed toward opportunities on their economic merit, rather than being shaped by technical constraints.
Request a legacy audit
Identify hidden risks, security gaps, and performance bottlenecks in your current code.
Legacy software we modernize
We work with business-critical applications and platforms that carry real operational weight, including:
- Core transaction and processing systems.
- Custom ERP, CRM, and internal operational tools.
- Backend services and business logic layers.
- Complex integrations between internal and third-party systems.
- Data platforms, reporting pipelines, and analytics foundations.
- Legacy web, desktop, and hybrid applications that have grown over the years.
If it runs a core process, holds critical data, or connects multiple parts of the business, we know how to modernize it.
Legacy application modernization services
Legacy modernization is a sequence of challenges that require diverse types of work, decisions, and risk management. We structure our application modernization services so you can engage exactly where your system is stuck: with detailed costs of each step and clear results.
Legacy system assessment & consulting
Assessment and consulting serve one goal: to provide clarity before significant technical and financial decisions are made. When systems have grown over the years, most risks live in undocumented dependencies, implicit business rules, fragile integrations, and assumptions that no one fully trusts anymore.
What we do
We examine how the system actually operates today, including architecture, data flows, operational behavior, and business constraints. Attention is paid to real dependencies, implicit rules, and areas where risk has accumulated over time. We prepare an as-is system description that provides technical and business stakeholders with a common reference point for discussion and planning.
The results
As a result, you receive a clear system map, defined risk zones, and realistic modernization options with trade-offs. Priorities, scope boundaries, and constraints are set upfront. This allows modernization decisions to be made deliberately and defended with facts.
Application & architecture modernization
This service makes business-critical systems easier to run and safer to change. We update application architecture so systems stay stable in production and support ongoing work without disrupting operations.
What we do
We refactor and reorganize application components to lower coupling, steady core business logic, and set clear architectural boundaries. This limits how changes spread through the system and reduces incidents caused by routine updates, integrations, or fixes.
The results
Releases follow a predictable pattern, incidents occur less often, and teams plan work with fewer unknowns. The system handles regular development, stays reliable under load, and continues to support core business processes as requirements change.
Cloud & infrastructure modernization
Infrastructure often grows unevenly over time, shaped by fixes, exceptions, and manual routines. Scaling becomes tense, costs become harder to track, and reliability depends on individual knowledge.
What we do
We modernize infrastructure so stability, scaling, and recovery are built into the environment. Hosting, environments, and deployment pipelines are redesigned to match operational needs, regulatory requirements, and cost limits. The infrastructure behaves consistently under load, recovers cleanly from failures, and supports change without manual intervention.
The results
After modernization, infrastructure becomes predictable. Deployments follow a routine process, recovery paths are defined, and capacity adjusts with demand. Operations teams spend less time reacting and more time improving, while the business relies on a stable foundation as usage and requirements grow.
Data & platform modernization
In many legacy environments, data is spread across systems with unclear ownership and uneven quality. Reports differ, access is inconsistent, and teams rely on manual extracts. Decisions slow down because data cannot be trusted or used directly.
What we do
We examine how data is defined, stored, and exchanged across systems, identify inconsistencies and weak integration points, and redesign data models and integration flows to create a coherent structure. This includes aligning key entities, clarifying data ownership, and restructuring how data moves between systems.
The results
Teams work with the same data, reports align, access no longer depends on manual effort, and data can support reporting, compliance, and automation without creating new operational risk.
Our recent works
The system has produced a significant competitive advantage in the industry thanks to SumatoSoft’s well-thought opinions.
They shouldered the burden of constantly updating a project management tool with a high level of detail and were committed to producing the best possible solution.
I was impressed by SumatoSoft’s prices, especially for the project I wanted to do and in comparison to the quotes I received from a lot of other companies.
Also, their communication skills were great; it never felt like a long-distance project. It felt like SumatoSoft was working next door because their project manager was always keeping me updated. Initially.
We tried another company that one of our partners had used but they didn’t work out. I feel that SumatoSoft does a better investigation of what we’re asking for. They tell us how they plan to do a task and ask if that works for us. We chose them because their method worked with us.
SumatoSoft is great in every regard including costs, professionalism, transparency, and willingness to guide. I think they were great advisors early on when we weren’t ready with a fully fleshed idea that could go to market.
They know the business and startup scene as well globally.
SumatoSoft is the firm to work with if you want to keep up to high standards. The professional workflows they stick to result in exceptional quality.
Important, they help you think with the business logic of your application and they don’t blindly follow what you are saying. Which is super important. Overall, great skills, good communication, and happy with the results so far.
They are very sharp and have a high-quality team. I expect quality from people, and they have the kind of team I can work with. They were upfront about everything that needed to be done.
I appreciated that the cost of the project turned out to be smaller than what we expected because they made some very good suggestions. They are very pleasant to work with.
The Rivalfox had the pleasure to work with SumatoSoft in building out core portions of our product, and the results really couldn’t have been better.
SumatoSoft provided us with engineering expertise, enthusiasm and great people that were focused on creating quality features quickly.
SumatoSoft succeeded in building a more manageable solution that is much easier to maintain.
When looking for a strategic IT-partner for the development of a corporate ERP solution, we chose SumatoSoft. The company proved itself a reliable provider of IT services.
Thanks to SumatoSoft can-do attitude, amazing work ethic and willingness to tackle client’s problems as their own, they’ve become an integral part of our team. We’ve been truly impressed with their professionalism and performance and continue to work with a team on developing new applications.
We are completely satisfied with the results of our cooperation and will be happy to recommend SumatoSoft as a reliable and competent partner for development of web-based solutions
Together with the team, we have turned the MVP version of the service into a modern full-featured platform for online marketers. We are very satisfied with the work the SumatoSoft team has performed, and we would like to highlight the high level of technical expertise, coherence and efficiency of communication and flexibility in work.
We can say with confidence that SumatoSoft has realized all our ideas into practice.
Get a modernization roadmap
Receive a phased, low-risk plan to upgrade your software without disrupting operations.
Risk & continuity – how we avoid downtime
For most organizations, modernization risk comes from disrupting systems that carry revenue, operations, or compliance. We design change so systems stay stable while updates are introduced in a controlled and verifiable way.
No-downtime and minimal-downtime execution
Modernization is planned around live systems. When downtime is not acceptable, we use phased releases, parallel environments, traffic switching, and incremental cutovers. Each step is isolated and checked before moving on. When downtime is required, it is limited, planned in advance, and agreed on with stakeholders.
Data integrity and safe migration
We treat data integrity as a first-class engineering constraint. Before migration, we create full backups and validate schemas, constraints, and dependencies. We rehearse migrations in production-like staging environments, execute changes atomically, and verify results using record counts and consistency checks before any cutover. All validation steps are repeatable and traceable, so data remains complete, consistent, and auditable after the move.
Testing before release
Changes are validated before reaching production. We test business flows, integrations, performance limits, and failure scenarios. Tests run in environments close to production, with realistic data volumes and traffic. Issues surface early, when they are easier to fix.
Coexistence of old and new components
Modernization unfolds step by step. We shape systems so existing and updated components can operate alongside each other without conflict. Roles are delineated, interfaces are explicit, and interactions are observed. This allows individual parts to be swapped out, adjusted, or reversed on their own, without disturbing the rest of the system.
Controlled rollback and recovery
Every change is delivered with a predefined rollback and recovery plan. We prepare rollback paths before release, verify them in non-production environments, and ensure they can be executed without cascading side effects. This keeps recovery time predictable, limits blast radius, and allows teams to revert changes quickly while preserving system and data integrity.
Choose your modernization path
There is no universal modernization playbook, nor is there a single legacy application modernization service. Even within one system, different parts often call for different moves. The choice depends on how exposed a component is, how worn it has become, and how much uncertainty the business can tolerate. We look at each case separately and pick a strategy that moves things forward without shaking live operations.
Rehost / Replatform
This option is about taking pressure off the infrastructure. The system is moved to a newer environment with little change to behavior or features. The aim is to step away from failing hardware, outdated platforms, and fragile setups that demand constant attention. This path is usually chosen when time, continuity, and spending discipline matter more than internal cleanup.
What you get: a quicker exit from legacy infrastructure, steadier operation, and a cleaner starting point for future work.
Refactor
This option deals with internal tangles. We straighten out core logic, surface hidden couplings, and refresh key components so the system becomes less risky to touch. Refactoring makes sense when the system still earns its keep, but its inner structure slows change and amplifies mistakes.
What you get: calmer releases, fewer surprises during changes, and lower day-to-day maintenance without disturbing core workflows.
Rearchitect
This option is chosen when the system is running into its structural limits. We redraw boundaries, split responsibilities more clearly, and reshape the architecture so it can handle higher load, new integrations, and broader use cases. Rearchitecting is used when small fixes stop paying off.
What you get: room to scale, clearer ownership across components, and a structure that won’t collapse under future demands.
Rebuild
This option applies when the existing system has reached the end of its useful life. We recreate critical functionality with modern tools and patterns, while carefully handling data transfer and continuity of operations. Rebuilding is a strategic move, not a reflex.
What you get: a fresh system that matches how the business works today and how it is likely to work tomorrow.
Retire
This option removes systems that have outlived their purpose. We identify software that no longer pulls its weight, shut it down safely, and stop paying for its upkeep. Retirement cuts noise and frees capacity for work with real impact.
What you get: lower running costs, fewer moving parts, and a less cluttered system landscape.
Rehost / Replatform
This option is about taking pressure off the infrastructure. The system is moved to a newer environment with little change to behavior or features. The aim is to step away from failing hardware, outdated platforms, and fragile setups that demand constant attention. This path is usually chosen when time, continuity, and spending discipline matter more than internal cleanup.
What you get: a quicker exit from legacy infrastructure, steadier operation, and a cleaner starting point for future work.
Refactor
This option deals with internal tangles. We straighten out core logic, surface hidden couplings, and refresh key components so the system becomes less risky to touch. Refactoring makes sense when the system still earns its keep, but its inner structure slows change and amplifies mistakes.
What you get: calmer releases, fewer surprises during changes, and lower day-to-day maintenance without disturbing core workflows.
Rearchitect
This option is chosen when the system is running into its structural limits. We redraw boundaries, split responsibilities more clearly, and reshape the architecture so it can handle higher load, new integrations, and broader use cases. Rearchitecting is used when small fixes stop paying off.
What you get: room to scale, clearer ownership across components, and a structure that won’t collapse under future demands.
Rebuild
This option applies when the existing system has reached the end of its useful life. We recreate critical functionality with modern tools and patterns, while carefully handling data transfer and continuity of operations. Rebuilding is a strategic move, not a reflex.
What you get: a fresh system that matches how the business works today and how it is likely to work tomorrow.
Retire
This option removes systems that have outlived their purpose. We identify software that no longer pulls its weight, shut it down safely, and stop paying for its upkeep. Retirement cuts noise and frees capacity for work with real impact.
What you get: lower running costs, fewer moving parts, and a less cluttered system landscape.
Modernizing a live enterprise system is like performing surgery on a beating heart—there is no room for error. We approach legacy transformation with a strategy that prioritizes business continuity, ensuring that you evolve your technology without pausing your growth.
Calculate maintenance savings
See how much budget you can reclaim by eliminating technical debt and inefficient servers.
The real cost of maintaining a legacy system
Maintaining a legacy system gets more expensive every year. As technology, regulation, and customer expectations change, the system falls further behind business needs. Costs grow, but the biggest loss is missed opportunities and slower decisions.
- Rising maintenance costs – Legacy code relies on outdated frameworks, custom solutions, and undocumented logic. Fewer engineers can work with it, staffing becomes expensive, and knowledge concentrates in a small group. Simple changes take longer, testing expands, and maintenance gradually replaces new development.
- Lost opportunity costs – teams spend their time keeping the system alive. New initiatives are postponed or dropped because the platform cannot support them safely. Integrations take months instead of weeks. Data stays locked in silos. Time-to-market slows, not because ideas lack value, but because the system cannot absorb change without risk.
How we modernize – the SumatoSoft approach
We modernize legacy systems through a structured process that combines deep technical understanding with disciplined risk management. Our goal is steady progress without loss of operational control.
We analyze architecture, dependencies, data flows, and operational behavior using both expert review and AI-assisted analysis. This turns legacy code and documentation into a shared knowledge base and exposes real risk, not assumptions.
We work with stakeholders to clarify goals, constraints, and acceptable risk. This step resolves ambiguity early and prevents modernization from stalling in the “messy middle” of competing opinions.
Based on evidence, we choose the appropriate strategy for each component – rehost, refactor, rearchitect, rebuild, or retire – focusing on continuity, compliance, and long-term usefulness.
We plan modernization in increments that deliver immediate pressure relief while moving the architecture toward long-term stability, scalability, and security.
We implement, test, and validate each step with rollback options and data integrity checks, keeping production stable throughout the process.
We stay involved after delivery to stabilize changes in production, monitor behavior, address emerging issues, and adapt the system as requirements, load, and regulations evolve.
Let’s start
If you have any questions, email us info@sumatosoft.com
Frequently asked questions
How long does modernization take?
It depends on system size, condition, and the chosen approach. An initial assessment usually takes a few weeks and defines the scope and sequence. Modernization then runs in phases over several months, with usable results delivered along the way.
Can we modernize without stopping operations?
In most cases, yes. Work is planned around live systems using phased releases, parallel environments, and controlled cutovers. If downtime is required, it is limited, planned in advance, and agreed on up front.
What happens to legacy data?
Data is kept and handled as a core asset. We migrate and validate it in stages, reconcile records, and confirm integrity before production cutover. Historical data remains available and compliant with regulations.
How is the cost estimated?
Cost is defined after assessment. Work is estimated by phase, based on technical complexity, risk, and business constraints. This avoids large upfront commitments and allows budget and scope to adjust as the system changes.
When is modernization not worth it?
Modernization may not make sense when a system is planned for retirement, replacement by a standard product, or no longer supports core processes. The assessment includes identifying cases where further investment does not pay off.
