Legacy System Modernization Companies

A neutral market map of companies delivering legacy system modernization, plotted by modernization approach and supplier layer. Alphabetical, never ranked or scored.

Updated 7 October 2026·Peter Korpak·Methodology

Compare legacy system modernization companies

Filter by what a company migrates from, its modernization approach, supplier type, team size, or region. Listed alphabetically, never ranked, scored, or rated. We currently have no sponsors. Vendor inclusion, recommendations, and highlights are editorial decisions based on documented evidence.

The lists show recorded source and target technologies. They do not prove delivery of every combination. Follow the public evidence links to the checked claims below. “Public sources not reviewed here” means we have not checked those claims; it is not a judgment of the supplier’s performance.

Migrates from:

Approach:

Supplier type:

Team size:

Region:

Legacy System Modernization company comparison: recorded source and target coverage, approach, supplier type, team size, region, public evidence kind, and internal relationship records
Company	Recorded source → target coverage	Approach	Type	Team size	Region	Public evidence kind
.NET Upgrade Assistant	Recorded source → target coverageCoverage not recorded	Approach Refactor	TypeProduct or platform	Team size—	Region—	Public evidence kindPublic sources not reviewed here	Internal relationship records0 internal relationship records
10Clouds	Recorded source → target coverageTo: AWS	Approach—	TypeDelivery firm	Team sizeMid-size	RegionPoland	Public evidence kindPublic sources not reviewed here	Internal relationship records0 internal relationship records
Abto Software	Recorded source → target coverage.NET Framework to .NET Core	Approach Refactor	TypeDelivery firm	Team sizeMid-size	RegionLviv, Ukraine	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Accenture	Recorded source → target coveragePowerBuilder to .NET	Approach RefactorRewrite	TypeDelivery firm	Team sizeEnterprise	RegionGlobal	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Appeon	Recorded source → target coverageCoverage not recorded	Approach RefactorRewrite	TypeProduct or platform	Team size—	Region—	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Avanade	Recorded source → target coverage.NET Framework to .NET Core	Approach Refactor	TypeDelivery firm	Team sizeEnterprise	RegionSeattle, WA	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
CAST Software	Recorded source → target coverageCoverage not recorded	Approach—	TypeDelivery firm	Team sizeEnterprise	RegionGlobal (HQ: New York)	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Cleveroad	Recorded source → target coverage.NET Framework to .NET Core	Approach Refactor	TypeDelivery firm	Team sizeMid-size	RegionDnipro, Ukraine	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Cognizant	Recorded source → target coveragePowerBuilder to .NET	Approach RefactorRewrite	TypeDelivery firm	Team sizeEnterprise	RegionGlobal (US HQ)	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
CSHARK	Recorded source → target coverage.NET Framework to .NET Core	Approach Refactor	TypeDelivery firm	Team sizeMid-size	RegionWroclaw, Poland	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
DevsData	Recorded source → target coverage.NET Framework to .NET Core	Approach Refactor	TypeDelivery firm	Team sizeMid-size	RegionUSA / Poland	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Embarcadero	Recorded source → target coverageDelphi to .NET	Approach RefactorRewrite	TypeDelivery firm	Team sizeMid-size	RegionUSA	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
EPAM Systems	Recorded source → target coverageDelphi, .NET Framework, Visual Basic 6 to .NET, .NET Core	Approach RefactorRewrite	TypeDelivery firm	Team sizeEnterprise	RegionGlobal (USA HQ)	Public evidence kindPublic sources not reviewed here	Internal relationship records3 internal relationship records
Feathersoft	Recorded source → target coverageVisual Basic 6 to .NET	Approach RefactorRewrite	TypeDelivery firm	Team sizeMid-size	RegionIndia	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Fresche Solutions	Recorded source → target coverageCoverage not recorded	Approach RefactorRewrite	TypeDelivery firm	Team size—	Region—	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Micro Focus	Recorded source → target coverageCoverage not recorded	Approach ReplatformRetain & optimize	TypeProduct or platform	Team sizeEnterprise	RegionGlobal	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Mobilize.Net	Recorded source → target coveragePowerBuilder, Visual Basic 6 to .NET	Approach RefactorRewrite	TypeDelivery firm	Team sizeMid-size	RegionUSA / Costa Rica	Public evidence kindPublic sources not reviewed here	Internal relationship records2 internal relationship records
Modernizing Medicine	Recorded source → target coverageCoverage not recorded	Approach—	TypeDelivery firm	Team sizeMid-size	RegionUSA	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
N-iX	Recorded source → target coverageDelphi, Visual Basic 6 to .NET	Approach RefactorRewrite	TypeDelivery firm	Team sizeMid-size	RegionEurope / Global	Public evidence kindPublic sources not reviewed here	Internal relationship records3 internal relationship records
OpenRewrite	Recorded source → target coverageCoverage not recorded	Approach Refactor	TypeProduct or platform	Team size—	Region—	Public evidence kindPublic sources not reviewed here	Internal relationship records0 internal relationship records
SoftServe	Recorded source → target coverageDelphi, PowerBuilder to .NET	Approach RefactorRewrite	TypeDelivery firm	Team sizeEnterprise	RegionGlobal (Ukraine Origins)	Public evidence kindPublic sources not reviewed here	Internal relationship records2 internal relationship records
Softura	Recorded source → target coverage.NET Framework to .NET Core	Approach Refactor	TypeDelivery firm	Team sizeMid-size	RegionFarmington Hills, MI	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Software Improvement Group (SIG)	Recorded source → target coverageCoverage not recorded	Approach—	TypeDelivery firm	Team sizeEnterprise	RegionNetherlands (Global coverage)	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
Thoughtworks	Recorded source → target coverageCoverage not recorded	Approach—	TypeDelivery firm	Team sizeEnterprise	RegionChicago, IL, USA (global)	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
TSRI	Recorded source → target coverageDelphi to .NET	Approach RefactorRewrite	TypeDelivery firm	Team sizeBoutique	RegionUSA	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record
VBUC (Visual Basic Upgrade Companion)	Recorded source → target coverageCoverage not recorded	Approach RefactorRewrite	TypeProduct or platform	Team size—	Region—	Public evidence kindPublic sources not reviewed here	Internal relationship records0 internal relationship records
vFunction	Recorded source → target coverageCoverage not recorded	Approach—	TypeDelivery firm	Team sizeMid-size	RegionUSA	Public evidence kindPublic sources not reviewed here	Internal relationship records1 internal relationship record

The count covers this site’s migration and service links for each company, listed under its entry. It does not count verified case studies or successful projects.

The checked public sources, scoped claims and limits for suppliers across hubs are published as an open vendor evidence dataset with CSV and JSON downloads.

Approach matrix

How Legacy System Modernization companies map to modernization approach

Rows group legacy system modernization companies by modernization approach, defined in our 7 Rs of application modernization framework; columns separate product vendors from delivery firms.

Refactor is the most common approach here, documented by 20 of 27 companies in legacy system modernization. Product vendors and delivery firms both cluster in Refactor.
Approach	Product	Delivery firm
Rehostsame code, new infrastructure or emulator	ProductNone documented	Delivery firmNone documented
Replatformsame core code, swapped runtime or managed services	Product Micro Focus	Delivery firmNone documented
Refactorthe existing code is converted or restructured in place	Product .NET Upgrade Assistant Appeon OpenRewrite VBUC (Visual Basic Upgrade Companion)	Delivery firm Abto Software Accenture Avanade Cleveroad Cognizant CSHARK DevsData Embarcadero EPAM Systems Feathersoft Fresche Solutions Mobilize.Net N-iX SoftServe Softura TSRI
Rewriterebuilt from scratch on a new architecture	Product Appeon VBUC (Visual Basic Upgrade Companion)	Delivery firm Accenture Cognizant Embarcadero EPAM Systems Feathersoft Fresche Solutions Mobilize.Net N-iX SoftServe TSRI
Replaceswapped for a commercial or SaaS product	ProductNone documented	Delivery firmNone documented
Retain & optimizekept in place and improved	Product Micro Focus	Delivery firmNone documented

6 companies are not plotted: no documented approach evidence.

What each company delivers in legacy system modernization

One entry per company, carrying only attributes we can point at a source for. Where a company has no published evidence for an attribute, nothing is shown rather than a placeholder.

Engagement bands in this domain

Small: $30K–$60K
Mid-market: $75K–$150K
Enterprise: $200K–$400K

Spans are the published pricing tiers on this domain’s service pages (Legacy Application Assessment Services), cross-checked against the cost benchmarks. A company is placed in a band by its team size — this is a statement about the size of engagement firms of that scale typically deliver here, not a rate card. We publish no per-vendor rates.

.NET Upgrade Assistant
Platform
Microsoft's free, open-source .NET Upgrade Assistant scans .NET Framework, ASP.NET, WPF, WinForms, and Xamarin Forms projects and walks a developer through upgrading project files and package references — but Microsoft deprecated it in 2026 in favor of the GitHub Copilot app-modernization agent, leaving the CLI still running without further active development.
Refactor
10Clouds
Agency
Lists AWS migration and re-architecting of legacy systems on its cloud migration page. No .NET Framework or .NET Core migration service or case study appears in the pages checked.
Modernizes to
AWS
Firm profile
Mid-size · Poland
Typical engagement band
Mid-market · $75K–$150K
Abto Software
Agency
Abto Software's .NET Framework-to-Core practice specializes in math- and algorithm-heavy applications, porting complex scientific and engineering calculation logic from desktop clients to web architectures.
Refactor
Best for
Complex algorithm porting (Desktop -> Web)
Modernizes
.NET Framework to .NET Core
Firm profile
Mid-size · Lviv, Ukraine
Typical engagement band
Mid-market · $75K–$150K
Internal research links
.NET Framework to .NET Core Migration Services
Accenture
Agency
Accenture's PowerBuilder-to-.NET migration practice operates at industrial scale, positioned for global enterprises running many PowerBuilder applications as one coordinated modernization program rather than piecemeal, application-by-application projects.
RefactorRewrite
Best for
Global enterprise systems
Modernizes
PowerBuilder to .NET
Firm profile
Enterprise · Global
Typical engagement band
Enterprise · $200K–$400K
Internal research links
PowerBuilder to .NET Migration Services
Appeon
Platform
PowerServer deploys client/server PowerBuilder applications as .NET Core-backed cloud applications; it preserves the PowerBuilder model rather than converting the codebase into a standalone C# application.
RefactorRewrite
Best for
Fastest path to web without rewrite
Internal research links
PowerBuilder to .NET Migration Services
Avanade
Agency
Avanade migrates .NET Framework applications to .NET Core within the Microsoft ecosystem, aimed at Fortune 500 estates consolidating onto Azure alongside the framework upgrade.
Refactor
Best for
Fortune 500 Azure Migrations
Modernizes
.NET Framework to .NET Core
Firm profile
Enterprise · Seattle, WA
Typical engagement band
Enterprise · $200K–$400K
Internal research links
.NET Framework to .NET Core Migration Services
CAST Software
Agency
CAST Highlight scans large application portfolios, up to 100-plus apps at a time, to prioritize which legacy VB6, PowerBuilder, or Delphi systems get migrated first — an assessment step, not a firm that performs the conversion.
Best for
Large portfolios (100+ apps) needing rapid assessment
Firm profile
Enterprise · Global (HQ: New York)
Typical engagement band
Enterprise · $200K–$400K
Internal research links
Legacy Application Assessment Services
Cleveroad
Agency
Cleveroad's .NET Framework-to-Core migrations concentrate on supply-chain and logistics software, most often replacing a warehouse-management system built on the older framework.
Refactor
Best for
Warehouse management systems
Modernizes
.NET Framework to .NET Core
Firm profile
Mid-size · Dnipro, Ukraine
Typical engagement band
Mid-market · $75K–$150K
Internal research links
.NET Framework to .NET Core Migration Services
Cognizant
Agency
Cognizant runs PowerBuilder-to-.NET migrations through its Skygrade platform, aimed at large portfolio rationalization — consolidating overlapping legacy applications rather than porting them one-for-one.
RefactorRewrite
Best for
Large portfolio rationalization
Modernizes
PowerBuilder to .NET
Firm profile
Enterprise · Global (US HQ)
Typical engagement band
Enterprise · $200K–$400K
Internal research links
PowerBuilder to .NET Migration Services
CSHARK
Agency
CSHARK's .NET Framework-to-Core migrations run mostly in fintech and regtech, where banking clients need the upgrade to satisfy compliance requirements.
Refactor
Best for
Banking apps needing compliance
Modernizes
.NET Framework to .NET Core
Firm profile
Mid-size · Wroclaw, Poland
Typical engagement band
Mid-market · $75K–$150K
Internal research links
.NET Framework to .NET Core Migration Services
DevsData
Agency
DevsData supplies senior .NET Core engineers as staff augmentation for in-house .NET Framework migration teams, rather than running the modernization as a packaged project.
Refactor
Best for
Adding senior .NET Core talent
Modernizes
.NET Framework to .NET Core
Firm profile
Mid-size · USA / Poland
Typical engagement band
Mid-market · $75K–$150K
Internal research links
.NET Framework to .NET Core Migration Services
Embarcadero
Agency
Embarcadero, the maker of Delphi and C++Builder, offers a path that keeps the codebase in Delphi and recompiles it for mobile and cloud targets, rather than rewriting it in C# or another language.
RefactorRewrite
Best for
Staying with Delphi but modernizing architecture
Modernizes
Delphi to .NET
Firm profile
Mid-size · USA
Typical engagement band
Mid-market · $75K–$150K
Internal research links
Delphi to C# Migration Services
EPAM Systems
Agency
EPAM runs full rewrites across Delphi-to-C#, VB6-to-.NET, and .NET Framework-to-Core migrations, treating them as re-engineering rather than a like-for-like port.
RefactorRewrite
Best for
Large scale rewrites
Modernizes
Delphi, .NET Framework, Visual Basic 6 to .NET, .NET Core
Firm profile
Enterprise · Global (USA HQ)
Typical engagement band
Enterprise · $200K–$400K
Internal research links
Delphi to C# Migration Services, .NET Framework to .NET Core Migration Services, Visual Basic 6 to .NET Migration Services
Feathersoft
Agency
Feathersoft runs standing VB6-to-.NET conversion teams rather than one-off consulting engagements, positioned as a lower-cost route through the repetitive, high-volume work of porting older desktop applications.
RefactorRewrite
Best for
Cost-effective porting
Modernizes
Visual Basic 6 to .NET
Firm profile
Mid-size · India
Typical engagement band
Mid-market · $75K–$150K
Internal research links
Visual Basic 6 to .NET Migration Services
Fresche Solutions
Agency
Fresche modernizes IBM i and Microsoft systems through code, application, cloud, and managed services; its reviewed public material does not establish a dedicated VB6-to-.NET conversion offering.
RefactorRewrite
Best for
Long-term support and evolution
Internal research links
Visual Basic 6 to .NET Migration Services
Micro Focus
Platform
Micro Focus's legacy-assessment work is documented on COBOL, Fortran, and PL/I mainframe and midrange estates, not on VB6, PowerBuilder, or Delphi desktop applications — most useful when a portfolio spans both mainframe and desktop legacy layers. The COBOL and mainframe tooling behind this has been owned by Rocket Software since May 2024.
ReplatformRetain & optimize
Best for
Mainframe and midrange application analysis
Firm profile
Enterprise · Global
Typical engagement band
Enterprise · $200K–$400K
Internal research links
Legacy Application Assessment Services
Mobilize.Net
Agency
Originator of the VBUC and WebMAP toolchain. Its application migration unit, including those tools and the Mobilize.Net brand, was sold to Growth Acceleration Partners in February 2023; GAPVelocity.ai now offers PowerBuilder and VB6 conversion to .NET and Blazor, and says its current AI-assisted process automates up to 95% of conversion.
RefactorRewrite
Best for
Moving off PowerBuilder entirely
Modernizes
PowerBuilder, Visual Basic 6 to .NET
Firm profile
Mid-size · USA / Costa Rica
Typical engagement band
Mid-market · $75K–$150K
Internal research links
PowerBuilder to .NET Migration Services, Visual Basic 6 to .NET Migration Services
Modernizing Medicine
Agency
Modernizing Medicine's legacy-assessment work is scoped to healthcare: HIPAA-compliant review of legacy EHR and patient-management systems, rather than the general-purpose VB6 or PowerBuilder estates a generalist assessment firm would cover.
Best for
HIPAA-compliant healthcare application assessment
Firm profile
Mid-size · USA
Typical engagement band
Mid-market · $75K–$150K
Internal research links
Legacy Application Assessment Services
N-iX
Agency
N-iX runs manual re-engineering — not automated conversion — across Delphi-to-C# and VB6-to-.NET migrations, aimed at reducing technical debt and cleaning up applications that need more than a straight port.
RefactorRewrite
Best for
Reducing technical debt during migration
Modernizes
Delphi, Visual Basic 6 to .NET
Firm profile
Mid-size · Europe / Global
Typical engagement band
Mid-market · $75K–$150K
Internal research links
Delphi to C# Migration Services, PowerBuilder to .NET Migration Services, Visual Basic 6 to .NET Migration Services
OpenRewrite
Platform
OpenRewrite is an open-source refactoring engine that applies versioned upgrade "recipes" to Java and Spring codebases, not the VB6, PowerBuilder, or Delphi desktop stacks. Running its recipes at scale across many repositories needs Moderne's commercial platform rather than the free CLI.
Refactor
SoftServe
Agency
SoftServe pairs Delphi-to-C# re-engineering for complex architectural changes with a UX-focused rebuild path for PowerBuilder-to-.NET migrations, aimed at legacy business apps whose interface — not just the backend — needs a full overhaul.
RefactorRewrite
Best for
Complex architectural changes
Modernizes
Delphi, PowerBuilder to .NET
Firm profile
Enterprise · Global (Ukraine Origins)
Typical engagement band
Enterprise · $200K–$400K
Internal research links
Delphi to C# Migration Services, PowerBuilder to .NET Migration Services
Softura
Agency
Softura's .NET Framework-to-Core work sits mostly in manufacturing and IoT, where the legacy .NET Framework app being replaced is often tied to industrial automation on the shop floor.
Refactor
Best for
Industrial automation apps
Modernizes
.NET Framework to .NET Core
Firm profile
Mid-size · Farmington Hills, MI
Typical engagement band
Mid-market · $75K–$150K
Internal research links
.NET Framework to .NET Core Migration Services
Software Improvement Group (SIG)
Agency
SIG benchmarks legacy codebases against the ISO 25010 quality standard, the kind of independently verifiable score buyers use for M&A technical due diligence rather than a migration recommendation.
Best for
M&A due diligence and quality benchmarking
Firm profile
Enterprise · Netherlands (Global coverage)
Typical engagement band
Enterprise · $200K–$400K
Internal research links
Legacy Application Assessment Services
Thoughtworks
Agency
Lists enterprise, mainframe, data platform and product modernization services, delivered with its AI/works agentic platform, and partners with Mechanical Orchard on mainframe work.
Best for
Organizations deciding the scope and sequence of modernization
Firm profile
Enterprise · Chicago, IL, USA (global)
Typical engagement band
Enterprise · $200K–$400K
Internal research links
Legacy Application Assessment Services
TSRI
Agency
TSRI's JANUS Studio automates Delphi and Pascal transformation to C#, aimed at organizations executing a complete exit from the Delphi ecosystem rather than staying on the platform under a modernized IDE.
RefactorRewrite
Best for
Complete exit from Delphi ecosystem
Modernizes
Delphi to .NET
Firm profile
Boutique · USA
Typical engagement band
Small · $30K–$60K
Internal research links
Delphi to C# Migration Services
VBUC (Visual Basic Upgrade Companion)
Platform
VBUC converts VB6 source code to C#, VB.NET, or Blazor, remapping the ADO/DAO data layer to Entity Framework Core and third-party library calls along the way. Growth Acceleration Partners bought it from Mobilize.Net in February 2023 and now sells it, licensed by lines of code, as GAPVelocity.ai's "VB6 AI Migrator."
RefactorRewrite
vFunction
Agency
vFunction analyzes Java monoliths using runtime and static analysis to auto-identify service boundaries — a Java microservices-readiness assessment, not a VB6, PowerBuilder, or Delphi migration.
Best for
Assessing Java apps for microservices migration
Firm profile
Mid-size · USA
Typical engagement band
Mid-market · $75K–$150K
Internal research links
Legacy Application Assessment Services

Market map

Companies to evaluate for Legacy System Modernization

Scope: published legacy system modernization companies with documented category, migration-path, or service evidence in this research domain.

Last evaluated 7 October 2026

208

Published modernization companies reviewed

Companies shown for legacy system modernization

Platforms 5Consultancies & integrators 22

Inclusion criteria: A company must have a published profile and documented category, migration-path, or service evidence in this domain. See the evidence threshold in our research methodology.

How to choose: Start with documented buyer fit (23 profiles) and specialty evidence (27), then narrow by team size (22) and location (22). Open a profile to verify the underlying experience before shortlisting.

This is an alphabetical market map, not an ordinal ranking. Inclusion is based on documented evidence and editorial review.

Legacy system modernization spans assessment platforms, transformation tools, replacement products, and delivery partners. Tool and platform vendors help inventory dependencies, analyze code, automate conversion, or supply the target system; consultancies and integrators plan sequencing, preserve business rules, migrate data, test equivalence, and manage cutover. Compare suppliers by legacy technology coverage, modernization-path fit, validation discipline, comparable evidence, delivery capacity, team size, and location. The alphabetical roster identifies companies to evaluate without assigning unsupported ordinal scores.