Legacy Software Modernization Companies in Canada (2026)

Most Canadian companies do not start with a blank page. They run on an ERP customized fifteen years ago, a line of business app written in a framework nobody hires for anymore, or a product a previous vendor left half finished. When that software starts to slow the business down, the question becomes who can safely change it. This guide compares Canadian firms that do legacy software modernization and software project takeover, using only facts you can verify.

We list firms alphabetically. We do not rank them, because the right legacy software modernization company for a federal mainframe is rarely the right one for a mid-sized SaaS product with a messy codebase. Use the table to narrow the field, then read the notes and the buyer guide to match a firm to your system and your risk tolerance. If you want the broader concepts first, our guide to application modernization covers the strategies in more depth.

How to choose a legacy modernization partner in Canada

Modernization projects fail for predictable reasons: the vendor underestimates the old system, the business cannot tolerate downtime, or knowledge walks out the door halfway through. A few questions filter most of the risk:

• What is the legacy platform? Mainframe COBOL, IBM i (AS/400), old .NET or Java monoliths, and aging PHP or Rails apps each call for different skills. Some firms specialize in one platform. Ask for case studies on yours.
• What strategy fits? Rehost, replatform, refactor, rebuild, or replace. A good partner recommends the smallest change that solves the business problem, not the biggest invoice.
• Can the old and new systems run side by side? Staged cutovers, where both versions run in parallel, keep revenue systems online during the move.
• Who owns knowledge transfer? Documentation, architecture notes, and access handover matter as much as the code. Ask how the firm documents what it learns about your system.
• Language and data residency. Québec organizations often need work delivered in French, and public sector or regulated buyers may need data kept in Canada. Confirm both up front.
• Verifiable proof. Third-party review profiles, published case studies, and real certifications beat superlatives. We cite those below.

Project takeover: inheriting a codebase from another vendor

Project takeover is a different job from modernization, and buyers often need it first. It happens when an agency missed deadlines, a freelancer disappeared, an internal team left, or a contract ended badly, and you are left with a codebase you cannot fully read. The goal is not a rewrite. The goal is to get the product stable, understood, and shipping again.

A sound takeover usually follows the same sequence:

• Secure access and ownership. Get the source repository, cloud accounts, domains, CI/CD pipelines, and third party credentials under your company's control. Confirm the contract assigns the IP to you.
• Audit before you build. A short code and infrastructure audit maps architecture, test coverage, dependencies, security gaps, and the real state of open features. It turns a vague worry into a prioritized list.
• Stabilize. Fix the crashes, security holes, and deployment problems first. New features wait until releases are predictable.
• Decide keep, refactor, or rebuild per module. Most inherited codebases have parts worth keeping. Replace only what blocks the roadmap.
• Document as you go. The new team should leave the system easier to hand over than they found it, so you never repeat the same lock in.

Not every modernization firm markets takeover work. In this list, Spiria states on its site that it takes over projects started by another vendor (source), and Webisoft runs a dedicated project takeover service. Ask any other firm directly whether it accepts inherited codebases and how it scopes the audit.

Legacy software modernization companies in Canada compared

The companies, in detail

Alithya

Alithya is a Montreal based digital strategy and technology company founded in 1992 by Ghyslain Rivard, originally under the name CIA (source). It reports more than 3,900 employees across Canada, the United States, and other countries (source). Alithya lists legacy systems modernization under its enterprise transformation services, and it cites application modernization expertise as part of its AWS Migration and Modernization Competency (source). Its broader practice spans ERP, CRM, business intelligence, and enterprise performance management (source), which makes it a natural option when modernization is part of a larger ERP or data program. Alithya tends to fit enterprises and public organizations that want modernization delivered alongside ERP, cloud, and data work.

CGI

CGI was founded as an IT consulting company on June 15, 1976, in Quebec City, and is now headquartered in Montreal with about 94,000 employees in roughly 400 offices worldwide (source). Its application modernization practice assesses portfolios and decides whether each application should be modernized, migrated, replatformed, consolidated, decommissioned, or replaced (source). For mainframes, CGI uses a proprietary automated tools environment called M8 and says migrations supported by it often finish within 6 to 12 months (source). CGI states its modernization work can deliver a 50 to 70% reduction in infrastructure and application maintenance costs, which is the firm's own claim (source). CGI tends to fit large enterprises and governments with mainframe estates, strict data residency needs, and the budget for a multi year program.

Corsac Technologies

Corsac Technologies is headquartered in Toronto and was founded in 2007, according to its Clutch profile, which shows a 5.0 rating across 5 reviews (source). The company lists 70+ specialists (source). Legacy software modernization is a core service, with a scope it describes as running from addressing tech debt and reinventing a tech stack to consulting and full implementation, and it can rewrite code from scratch or deliver individual modules (source). Its site says most app modernization projects take from 3 to 9 months (source). Corsac tends to fit mid-market companies that want to modernize a core application in stages and replace only the parts that need to change.

Euristiq

Euristiq was founded in 2016 and is headquartered in Toronto, with delivery teams in Warsaw, Poland and Lviv, Ukraine (source). Legacy modernization is a core focus: the company says its AI powered approach modernizes outdated software 60 to 80% faster, which is a vendor claim (source). One published case describes consolidating 60+ legacy modules built over 30 years into a single platform (source). The site also references PIPEDA compliant delivery for Canadian clients (source). Euristiq tends to fit organizations with sprawling, multi module legacy systems that want a Canadian contract with a European delivery team behind it.

Fresche Solutions

Fresche Solutions was launched in Montreal in 1976 by Ian Farquharson and Jean-Pierre Théorêt and describes itself as a global IBM i modernization partner (source). Clutch lists the firm in Montreal (source). Its offerings cover application services, managed services, cloud, data analytics and AI, and proprietary software for IBM i and Microsoft environments (source), with distributed teams across North America, India, Costa Rica, and Ukraine (source). Fresche tends to fit organizations whose core business still runs on IBM i (AS/400) and that want a specialist rather than a generalist.

Net Solutions

Net Solutions has been engineering software since 2000 and lists offices in Los Angeles, New York, Toronto, London, and Chandigarh, India, including a Toronto office on Queen Street East (source). Its application modernization practice covers replatforming, data engineering, and cloud migration on revenue critical systems, with old and new systems run in parallel during a staged cutover (source). Clutch lists the firm in Toronto with a 4.7 rating across 54 reviews (source). Net Solutions tends to fit commerce and revenue critical platforms that cannot afford a hard cutover.

Spiria

Spiria was founded in Canada in 2003 and has bilingual experts in Montreal, Gatineau, and Toronto (source). Its Clutch profile lists Montreal as headquarters, 50 to 249 employees, and a 4.9 rating across 27 reviews (source). Spiria offers application modernization, which it describes as updating existing systems without disrupting operations, and it states that it takes over projects started by another vendor, then consolidates the architecture and closes quality and security gaps (source). Spiria tends to fit Canadian organizations that want a bilingual local partner for both modernization and takeover work.

Underlabs

Underlabs Inc. was founded in 2009 and is headquartered in Montreal, with 10 to 49 employees according to its Clutch profile (source). Its service lines include custom software development, mobile app development, enterprise app modernization, and AI consulting and development, and it holds a 4.9 rating across 7 reviews (source). Underlabs tends to fit smaller organizations that want a boutique Montreal team for a focused modernization or mobile project.

Webisoft

Webisoft is a Montreal based software development firm founded in 2016, with a second office in Miami (source). It offers legacy product transition for teams moving an aging product to a modern stack, and a separate project takeover service for companies inheriting a codebase from another vendor. Its engineers are senior and based in North America, and the team works in English and French (source). Webisoft is AICPA SOC 2 Type II and HIPAA compliant, an AWS Partner, and an Odoo Partner (source), and it holds a 4.9-star rating across 23 reviews on Clutch (source). As the publisher of this article, we hold our own entry to the same sourcing standard as every other firm. Webisoft tends to fit companies that need to rescue or modernize a product with a senior, bilingual team in an Eastern time zone and security compliance already in place.

Modernization strategies and how engagements are scoped

Most vendors describe the same menu of strategies, so it helps to know what each one buys you:

• Rehost. Move the application to new infrastructure, often the cloud, with little code change. Fast, but it carries the old design forward.
• Replatform. Move to a new runtime or database with targeted changes. A common middle path for aging .NET, Java, and IBM i workloads.
• Refactor. Restructure the code to remove tech debt while keeping behavior the same. Good when the business logic is sound but the code is hard to change.
• Rebuild. Rewrite modules or the whole product on a modern stack. Highest cost and risk, and justified only when the old system blocks the roadmap.
• Replace. Retire custom software in favour of a packaged product such as an ERP. Works when your process is standard and the custom system adds no edge.

Engagements usually start with a paid discovery or audit phase, then move to time and materials or a dedicated team for the migration itself. Fixed bids are rare for legacy work because nobody fully knows the old system until they open it. Be wary of a firm that quotes a full rewrite before it has read the code. To benchmark budgets, see our breakdown of software developer rates in 2026 and our guide to app development cost.

A short buyer guide

Once you have a shortlist, run the same evaluation on every firm:

• Ask for a case study on your platform. Mainframe, IBM i, and web monolith work are different trades.
• Request a written audit before a full estimate. The audit is where a firm proves it understands your system.
• Insist on a parallel run or rollback plan. You should be able to fall back to the old system if a cutover goes wrong.
• Confirm code ownership and access. Your company should hold the repository, cloud accounts, and credentials from day one.
• Verify reviews and certifications yourself. Open the Clutch profile and ask for current compliance documentation such as SOC 2 reports.

Methodology note

We built this list from publicly verifiable information: each firm's own website, its Clutch profile or Clutch's Canadian application modernization directory (source), and neutral references such as Wikipedia. Every factual claim links to its source. We did not invent ratings, scores, or rankings, and where a fact such as a founding year or headquarters was not clearly stated we noted the gap rather than guess. Percentages quoted from vendors are their own claims, not independent measurements. Firms appear alphabetically, not ranked, and Webisoft, the publisher, sits in its natural alphabetical position. Company details change, so confirm current facts with any vendor before you sign.

Legacy software does not have to be a liability. Pick a partner that understands your platform, start with an audit, and modernize in stages you can roll back. If you are inheriting a product from another vendor or planning a move off an aging stack, see our legacy product transition and project takeover services, or read more in our application modernization guide.

Related software guides

• Application Modernization Guide
• Top Custom Software Development Companies in 2026
• Software Developer Rates in 2026

Ready to move forward? See our legacy product transition or talk to our team.