Modernising Legacy Visual Basic

Breaking point to breakthrough

Modernising your legacy Visual Basic applications using AI

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Industry trends and challenges

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Background

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Drivers for modernisations

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Modernisation strategies

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Evolve Legacy

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Our AI powered Modernisation Approach

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Decipher: Generative AI powered auto documentation

20-21

Benefits of partnering with us

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Customer Case stories

24-25

Pilot offering

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Our Authors John Bolger Global Lead for Application Modernisation and Integration

Miguel Vilhena Technology Principal for Digital, Data and Cloud

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Industry trends and challenges Running and maintaining legacy Visual Basic applications often creates significant challenges for businesses. Aside from often oppressive costs and lack of available skills on the market, some of the primary issues are the technical and compliance risks associated with managing outdated IT systems and applications that are no longer supported.

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50 %

60 %

Over half of the surveyed companies list increasing security and improving efficiency as main drivers for the modernisation of their legacy applications and data in 2023. Cost

… over two-thirds of businesses still use mainframe or legacy apps for core business operations, and more than 60% rely on them to power customer-facing applications.

reduction, better integration with modern technologies and increased agility and

Forbes (2022)

flexibility are not far behind, being mentioned by nearly 50 percent of the respondents as well.

Statista

These vulnerabilities and inefficiencies can result in risks that, if unchecked and exploited, could create financial and reputational risk, ie. systems unavailable due to ransomware or fines imposed due to noncompliance with NIS2.

Beyond technical risks, financial overheads present a major obstacle when maintaining legacy systems. Maintenance often requires dedicated personnel with specialist skills, third-party support, and infrastructure investments. These costs can quickly add up and strain a company’s budget, diverting resources away from more strategic initiatives.

The inability to innovate is another significant

Outdated technologies, such as those built on older architectures like Visual Basic, can hinder a business’s transition to cloud-based solutions and modern architectures. This creates a barrier to modernisation and prevents companies from leveraging the power of AI. Until now, updating legacy applications has been costly, time consuming and not without a high degree of risk, leaving some businesses with no option but to manage the status quo.

The intent of this eBook is to outline our innovative, tried and tested approach to a rapid, low cost/low risk legacy application migration methodology with our unique AI-based Visual Basic modernisation framework , the benefits this approach delivers, our customer success stories and how you can engage in our pilot program that delivers modernisation results within five days.

hurdle. Legacy applications can limit a company’s ability to stay competitive in a rapidly evolving market.

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Visual Basic background

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Historical context and evolution

Use cases for Visual Basic

Visual Basic (VB) released in 1991, gained

Visual Basic, particularly VB6, dominated desktop

prominence by offering a rapid application

app development in the 1990s and early 2000s,

development (RAD) environment for Windows,

enabling rapid creation of applications linked to

enabling developers to quickly build graphical

backend databases.

interfaces and link them to backend data sources.

Despite significant CPU and memory on the

Despite the evolution of software architecture and

user’s own device or virtual desktop

the introduction of VB.NET and C#, many

infrastructure, many VB applications remain

businesses continued using classic VB due to the

active due to their stability and integration with

cost, risk, and complexity of rewriting legacy

business processes leading to significant and

applications.

undesirable unbudgeted OPEX and CAPEX. They underpin critical operations like finance, logistics, customer management, and reporting, with migration risks keeping them vital for business continuity.

Powering core business systems

Architectural differences: then vs now

While many VB6 applications serve primarily as

Classic VB applications are monolithic, with tightly

back-office systems supporting internal users for

coupled UI, business rules, and data access which

business operations, a significant number still play

must be deployed to each end user device, unlike

a role in customer-facing services.

modern, service-based, cloud-deployed systems.

This is often the result of earlier modernisation

Current architectures use MVC or microservices

strategies where organisations opted to replace

for scalability and maintainability, optimised for

only the customer-facing user interfaces while

the web with REST APIs and asynchronous

retaining and encapsulating the original VB6

processing, presenting significant migration

business logic in the back office. These legacy

challenges for legacy VB systems.

components remain deeply embedded in organisations reflecting the complexity and risk involved in fully replacing them, which has often led businesses to defer full-scale reengineering.

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Drivers for modernisation There are many reasons for modernising legacy VB systems, which generally relate to reducing risk and cost. However, modernisation ultimately also allows you to leverage new functionalities and stay competitive in a rapidly evolving market.

• Reduce organisational risk by moving to a supported technology stack

• Reduce hardware and licensing costs

(e.g. Citrix or on-prem infrastructure)

• Improve scalability, performance, and user experience

• Improve and optimise business processes constrained by what is allowed by the underlying systems

• Align with cloud-first or digital transformation strategies

• Attract developer talent, as VB skills are increasingly rare

• Decrease technical debt and future-proofing core business systems

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Understanding the challenges Visual Basic modernisation presents a variety of unique technical challenges that require specialised expertise and careful planning to fulfil. Understanding these challenges is essential for developing effective modernisation strategies.

Tightly coupled code that mixes

Changes in architecture making

hard to extract and reuse

transform to modern architecture

Outdated dependencies

Hardware reliance,

lack modern equivalents

were designed for on-premise

UI and business logic, making it

and third-party components that

it more difficult to automatically

especially where applications servers or ‘thick-client’ PCs

Performance bottlenecks

Insufficient knowledge

platforms, which operate with

developers no longer being

different resource models and

present and lack of adequate

latency considerations

documentation

Difficulty comprehending

Size and complexity

longer taught to current

modernise - over the last 20 years

generation of software engineers

the smaller and simpler VB6

when migrating to web-based

the source code as VB is no

of the system itself, due to original

of the applications that are yet to

applications will have been modernised, and what’s left currently are the bigger, business critical applications 9

Modernisation strategies These strategies are tailored by business need.

In our view, a successful modernisation journey starts with understanding the role the application plays in your business.

Modernisation strategies depend on your unique circumstances.

There is no one-size-fits-all approach and every organisation operates within a unique set of

Customer example: Aligning applications to business needs In a recent engagement with one of our customers, they maintained a mission critical Visual Basic application with 5.5 million lines of code. As this codebase was too large and too risky to rebuild from scratch, we used automation technology to perform code transformation at scale, automatically converting VB6 to .NET using a combination

technical debt to business priorities, compliance requirements, and in-house capabilities. That’s why we evaluate a spectrum of modernisation strategies tailoring our approach to suit your specific context.

At the core of our process is a relentless focus on delivering business value. Our recommendations are grounded in pragmatism, carefully balancing the need for innovation with continuity and risk management.

of 3rd party product and GenAI.

This ensures that the modernised application not

We limited change as part of the conversion

aligns seamlessly with your organisation’s

process to reduce risk and enable us to quickly address the technology obsolescence issue and deliver the solution in a phased approach. This has enabled a move towards a continuous modernisation agenda once on .NET that allows us to realign the application to business needs.

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constraints; ranging from legacy architecture and

only leverages modern technologies but also strategic, technical, and operational objectives.

At the core of our process is a relentless focus on delivering business value 11

Rapid Proof of Concept With access to source code and data Version 1 can recreate a screen to demonstrate what modernised application will look like

Evolve or Transform Analysis to examine like-forlike code conversion vs benefits of transformative approach

Decipher & Dead Code Scan Version 1’s code analysis tool can automatically produce system documentation based on code inspection and identify redundant code

Options Assessment Quantitative analysis on success viability and sectoral/technical scan on legacy modernisation options

VB Conversion Toolkit Version 1’s pre-configured suite of tools and methods for converting legacy Visual Basic to modern code base

Stakeholder Mapping Identification of technical and business resources that may be impacted through the modernisation journey

Patterns & Accelerators Cloud landing zone blueprints, data models, LLM templates and integration patterns to facilitate legacy transition

Classification: Controlled

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Busin

Engag Champ associa and op

Legacy Identification Scanning & review of application landscape to identify priority legacy candidates

Classification: Controlled. Copyright ©2025 Version 1. All rights

Our Proven Framework Modular Prototyping Code conversion trials using range of technologies, including VBUC from the VB Conversion Toolkit

Modern Production Code Fully tested, Cloud-hosted, VB-free, production-ready code

Supporting Documentation System documentation drafted by Decipher, finalised by Version 1 engineers

Migration & Archiving Analysis and incorporation of historic data, user accounts and even regulatory audit logs into the modernised application

Target Tech Stack Application modernisation to .NET, C# or alternative technology

Deployment Automation Cloud, package and test automation of modernised candidate code

Managed Service Ready Code suitable for ongoing support through the Version 1 ASPIRE service

ness Chage

gement of Business pion to support any ated change, training perational impact

s reserved.

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Our Proven Framework 14

Rapid Proof of Concept

Modular Prototyping

With access to source code and data Version 1 can recreate a screen to demonstrate what modernised application will look like

Code conversion trials using range of technologies, including VBUC from the VB Conversion Toolkit

Modern Production Code Fully tested, Cloud-hosted, VB-free, production-ready code

Supporting Documentation

Evolve or Transform Analysis to examine like-forlike code conversion vs benefits of transformative approach

System documentation drafted by Decipher, finalised by Version 1 engineers

Decipher & Dead Code Scan Version 1’s code analysis tool can automatically produce system documentation based on code inspection and identify redundant code

Options Assessment Quantitative analysis on success viability and sectoral/technical scan on legacy modernisation options

Migration & Archiving Analysis and incorporation of historic data, user accounts and even regulatory audit logs into the modernised application

Target Tech Stack Application modernisation to .NET, C# or alternative technology

VB Conversion Toolkit Version 1’s pre-configured suite of tools and methods for converting legacy Visual Basic to modern code base

Stakeholder Mapping Identification of technical and business resources that may be impacted through the modernisation journey

Patterns & Accelerators Cloud landing zone blueprints, data models, LLM templates and integration patterns to facilitate legacy transition

Classification: Controlled

Deployment Automation Cloud, package and test automation of modernised candidate code

Managed Service Ready Code suitable for ongoing support through the Version 1 ASPIRE service

Business Chage Engagement of Business Champion to support any associated change, training and operational impact

Legacy Identification Scanning & review of application landscape to identify priority legacy candidates

Classification: Controlled. Copyright ©2025 Version 1. All rights reserved.

Based on our deep expertise in delivering Visual Basic modernisation programs, we have developed a tried and tested transformation framework which derisks and accelerates your journey.

This framework ensures consideration of the many factors that influence your modernisation strategy.

Our Evolve Legacy Visual Basic framework addresses all stages of the process, ensuring we fully consider and adapt our approach based on your unique circumstances:

Foundations

is our tried and tested toolkit we use to perform the modernisation

Pulse

ensures we understand the business context and drivers

Discover

delves into the details of what a transformation might look like

Experiment

enables us to rapidly assess and validate the future state solution

This framework includes a combination of our own IP such as our Decipher Generative AI Auto Documentation solution and our Business Value Assessment framework, through to the use of industry leading software that can automate the conversion from Visual Basic to modern .NET solutions, thus highly accelerating delivery.

Prioritise

ensures we break the problem down to derisk the process and deliver business value most effectively

Execute

governs how our teams deliver a production ready solution 15

Our AI powered approach Generative AI will unleash application modernisation at scale, enabling applications which would previously have cost too much or taken too long to be transformed.

Breakthroughs in the coding capabilities of Large Language Models have enabled this new reality, with AI now automating the tedious and manual intensive conversion process, and accelerating the development cycle, thus driving new levels of efficiencies. Our Visual Basic Modernisation solution employs Generative AI technology throughout the process.

Reduced effort of code conversion by

Reduc

75% using automation and Generative

using

AI technology

Auto documentation

Automated code conversion

AI assisted development

Use our Decipher GenAI solution to

Using best of breed AI coding assistants

generate documentation for your existing

to drive productivity enhancements of

systems, reducing effort by 80%

development by ~20%

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New developments in AI, particularly in gen AI, are radically recalibrating the costs and benefits of modernizing legacy tech and reducing tech debt as part of a larger set of changes in how IT operates.

McKinsey

ce test case creation by up to 50%

g our GenAI E2E test automation framework

AI assisted test automation

AI cloud provisioning

Accelerating Terraform scripting for environment creation by up to 50%

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Decipher: Gen-AI powered auto documentation Decipher is our Generative AI powered auto documentation solution to generate documentation from source code at scale.

This drives deep codebase analytics such as call

It offers an intuitive interface for analysis and

Generative AI auto documentation capability

stack analysis, automatic identification of individual business processes with the ability to isolate your most complex processes, obsolete code detection and business domain mapping.

This code analytics capability, coupled with our

documentation viewing and produces

enables Decipher to drive deep insights into your

documentation in a developer friendly and editable markdown format, which can be pushed to your source code repository and amended

Visual Basic application thus derisking and accelerating the modernisation journey.

Find out more about Decipher

as needed.

Decipher incorporates Visual Basic code analytics capabilities which enables deep insights into your application. It achieves this by plotting classes and functions onto a knowledge graph, whilst capturing the interconnectedness of code.

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Read source code

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Plot code on graph

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AI translation

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Generate documentation

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Query insights

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Benefits of partnering with us Our unique approach, our credibility, capability and unique IP

Award-winning results

Proprietary AI tools

Our National Highways VB6 modernisation

•

earned Microsoft’s 2023 Global Application

generation that automatically maps legacy

Modernization Award, demonstrating proven capability at the highest level.

Decipher: GenAI-powered documentation system logic.

•

Custom transformation Gen AI templates:

WinForms to Blazor conversion prompt and

Deep VB expertise

code templates that recently saved a client 400 development days.

Visual Basic modernisation requires specialised knowledge that’s increasingly rare in the market.

Our consulting team combines decades of VB experience with cutting-edge AI capabilities.

Scale-tested methodology

Azure Cloud Native Development accelerator Best practice accelerator focused on providing an opinionated implementation of Non-Functional

From rapid 3-month rebuilds to 5.5 million line

Requirements, including Terraform environment

transformations, our approach scales to match

creation, Cloud Configuration, DevOps pipelines,

project complexity using proven automation

starter for ten codebases and a comprehensive

combining automated VB Migration Tooling

test automation suite.

and GenAI technologies.

Cross-sector experience

Comprehensive modernisation playbook

Public sector, private enterprise, and financial

Our defined methodology reduces risk through

services organisations trust our modernisation expertise across diverse regulatory and operational requirements.

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repeatable processes refined across hundreds of successful transformations.

Relentless focus on protecting and driving business value

Full-stack capabilities Beyond code transformation, expertise spans cloud migration, data modernisation, AI integration, and user experience design for complete digital transformation.

Strategic partnerships Long-standing relationships with Microsoft and other cloud providers unlock funding opportunities and technical resources for your modernisation journey.

Proven track record Large-scale digital transformation programs consistently deliver measurable value and competitive differentiation for our clients.

Safe and secure use of AI We place the utmost importance on data privacy and security when using AI to modernise your applications.

Our AI partners which include Anthropic and GitHub share this commitment and guarantee that your business data is processed securely, is immediately deleted after use and is never used to train their AI models.

We maintain rigorous governance and oversight of all AI tools, ensuring they meet our stringent security standards. This means

User centred design This approach ensures modernisation focuses on realigning to your needs.

you benefit from AI-accelerated modernisation while maintaining complete control over your confidential information.

Your data is protected, your IP is secure and your trust is earned through our commitment to the highest standards of AI security.

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Customer case stories National Highways Our partnership with National Highways, included a rebuild of their VB6 app from scratch in 3 months as it was relatively small and self-contained.

We used our Azure Cloud Native Development accelerator as the starting point for this rebuild.

6-8 weeks Our accelerator saved between 6-8 weeks of delivery time and ensured a high-quality result.

Focused on providing a best practice and opinionated implementation of Non-Functional Requirements, this accelerator allowed our team to hit the ground running on the Visual Basic modernisation.

Our accelerator saved between 6-8 weeks of

150 %

delivery time and ensured a high-quality result.

The benefits of the transformed application

We were able to deliver better outcomes by

included 150% faster reporting of incidents,

applying User Centred Design to reimagine

more efficient incident closing, and a 50%

business processes.

increase in how fast reports can be created.

The benefits of the transformed application included 150% faster reporting of incidents, more efficient incident closing, and a 50% increase in how fast reports can be created.

These results led to improved journey times, easier navigation and ultimately increased safety for every person travelling across these major arteries in England, which carry up to 4 million vehicles a day. Our holistic and business value centred modernisation approach earned us Microsoft’s 2023 Global Application Modernization award.

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National Highways’ NILO reporting is now a faster, more comprehensive service than ever before ensuring road users have a better experience, less stressful journeys and improved journey times when travelling.

Tim Priest, National Operations Team Leader

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SCA Containerboard Our client’s application had 5.5 million lines of code and therefore too large and too risky to rebuild from scratch. In this scenario, we used deterministic rules-based automation, enhanced with Generative AI-assisted code generation, to perform code transformation to .NET and deal with the technology obsolescence.

By following a continuous modernisation agenda once on .

NET, it allowed us to realign the application to business needs. Due to the size and criticality of this application, we took an incremental transformation approach, where functionality was migrated module-by-module to reduce risk, with the initial two modernised modules already deployed in production, delivering a state of the art technology system.

A ‘best shoring’ delivery model was also utilised to realise cost efficiencies.

“63% decrease in delivery time due to automation” 23

More resources For more information on our legacy system modernisation, review the resources below.

Legacy system modernisation

Decipher

App modernisation blogs

Embrace innovation and

AI powered code analysis

Review our application

unleash agility by

and documentation.

modernisation blogging

modernising your legacy

content written by our

systems.

thought leaders and experts.

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Pilot Offering Prove the value: Your five day VB to .NET pilot Unlock the potential of your legacy VB6 applications with our low-risk, fixed-time pilot engagement. In just 5 days, we will take a representative slice of your existing codebase and transform it into a modern, maintainable .NET solution using our proven automation-first approach.

This pilot provides a tangible demonstration of the speed, quality, and business value our modernisation process can deliver, helping you build the confidence and clarity needed to move forward with a full transformation.

See the results, validate the approach, and de-risk your modernisation journey, all with minimal upfront investment.

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If you have a question on application modernisation or would like to take part in our pilot offering, please reach out to us to start your modernisation journey.

Talk to us today: info@version1.com version1.com