Montreal runs on old software more than most people realize. Insurers, manufacturers, distributors, and public bodies across Greater Montreal still depend on systems built ten, twenty, or thirty years ago: IBM i applications, aging .NET and Java monoliths, custom ERPs, and web platforms a past vendor left half finished. When that software starts to slow the business down, you need a partner who can change it safely, ideally one close enough to sit in the same room. This guide compares legacy software modernization companies in Montreal, using only facts we could verify on each firm's website, Clutch profile, or Wikipedia.
Use the table to narrow the field, then read each profile and the buyer guide to match a firm to your platform, your budget, and how much downtime you can tolerate. If you are comparing beyond the city, see our lists of legacy software modernization companies in Canada and legacy software modernization companies worldwide.
How to choose a legacy modernization partner in Montreal
Most modernization projects that fail do so for the same reasons: the vendor underestimates the old system, the business cannot afford downtime, or the people who understood the code leave halfway through. These questions filter most of that risk:
- What platform are you on? IBM i (AS/400), mainframe COBOL, old .NET or Java, and aging PHP or Rails apps call for different skills. Ask for a case study on your platform, not a generic modernization pitch.
- Is it modernization or a rescue? If a previous vendor left and nobody fully understands the code, you need a project takeover before any modernization plan makes sense.
- Can old and new run side by side? Staged cutovers keep revenue systems online. Ask how the firm runs both versions in parallel and how it rolls back.
- Do you need work in French? Many Québec organizations need documentation, interfaces, and meetings in French. A Montreal team usually handles both languages without extra cost or delay.
- Who owns what you learn? Architecture notes, runbooks, and access handover matter as much as the code. Your company should own the repository and cloud accounts from day one.
- Is the proof verifiable? Public reviews, named certifications, and published case studies beat adjectives. We link every claim below so you can check it.
Legacy software modernization companies in Montreal compared
| Rank | Company | Montreal presence | Founded | Specialties | Best for |
|---|---|---|---|---|---|
| 1 | Webisoft | Headquarters | 2016 | Legacy product transition, project takeover, SOC 2 Type II and HIPAA | Companies modernizing or rescuing a product with senior, bilingual engineers |
| 2 | Alithya | Headquarters | 1992 | Enterprise transformation, ERP, legacy systems modernization | Enterprises tying modernization to ERP, cloud, and data programs |
| 3 | CGI | Headquarters | 1976 | Application modernization, mainframe migration, managed services | Large enterprises and governments with mainframe estates |
| 4 | Fresche Solutions | Founded in Montreal | 1976 | IBM i modernization, managed services, software | Organizations running IBM i (AS/400) |
| 5 | Osedea | Headquarters | 2011 | Custom software, AI, data and BI modernization, SOC 2 Type 2 | Mid-market firms modernizing data heavy systems |
| 6 | Sigma Software | Office (opened 2020) | 2002 | Legacy assessment, modernization, migration and replatforming | Teams wanting a large international bench with a Montreal office |
| 7 | Spiria | Headquarters | 2003 | Application modernization, project takeover, custom software | Bilingual organizations wanting modernization and takeover from one firm |
| 8 | Underlabs | Headquarters | 2009 | Custom software, mobile apps, enterprise app modernization | Smaller teams wanting a boutique Montreal shop |
Sources for each row appear in the company profiles below.
The companies, in detail
1. Webisoft
Webisoft is a Montreal based software development firm founded in 2016, with a second office in Miami (source). It runs two services built for old and inherited software: legacy product transition, for teams moving an aging product to a modern stack in stages, and project takeover, for companies that inherit a codebase from another vendor, a freelancer, or an internal team that left. 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). Clutch lists its headquarters in Montréal, a team of 10 to 49 people, and a 4.9 rating across 23 reviews (source).
Why it fits this need: modernization and takeover sit under one roof, so a rescue can turn into a staged modernization without changing teams. The compliance controls are already audited, which matters when the old system holds customer, financial, or health data. Webisoft is smaller than the national firms on this list, so it is not the pick for a multi year mainframe program. It tends to fit companies with a product or line of business system that needs a senior, bilingual team in the Eastern time zone.
2. 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 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). Alithya tends to fit enterprises and public organizations that want modernization delivered as part of a larger ERP, cloud, or data program.
3. CGI
CGI was founded as an IT consulting company in 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 each application in a portfolio and decides whether it 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 and the budget for a multi year program.
4. 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's Canadian application modernization directory lists the firm in Montreal (source). Its offerings cover IBM i modernization, code and application transformation, database and UI modernization, managed services, 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 and that want a platform specialist rather than a generalist.
5. Osedea
Osedea lists Montréal as its headquarters on Clutch, with a founding year of 2011, a team of 50 to 249 people, and a 4.9 rating across 44 reviews (source). Its services span software development, digital product design, artificial intelligence, robotics, and data and business intelligence, and its site features an analytics and business intelligence modernization project (source). Its fintech page includes a case study titled "Conquering legacy code to elevate pension management" (source). Osedea states, "We are a SOC 2 Type 2 certified organization" (source). Clutch lists a minimum project size of $50,000+ and an hourly rate of $150 to $199 (source). Osedea tends to fit mid-market companies that want to modernize data heavy or AI ready systems with a local team.
6. Sigma Software
Sigma Software is an IT consulting company headquartered in Ukraine that opened its first Canadian office in Montréal in October 2020 (source). Clutch lists a founding year of 2002, a team of 1,000 to 9,999 people, a Montreal location among its offices, and a 4.8 rating across 37 reviews (source). Its legacy modernization and migration service covers technology consulting, technologies modernization, and migration and replatforming, and it starts with a legacy system assessment of functionality, dependencies, and bottlenecks (source). Clutch lists a minimum project size of $50,000+ and an hourly rate of $50 to $99 (source). Because it is an international firm with a Montreal office rather than a Montreal headquartered one, ask where your delivery team will sit. Sigma Software tends to fit organizations that need a large engineering bench and a lower blended rate for a long modernization program.
7. Spiria
Spiria was founded in Canada in 2003 and has bilingual experts in Montreal, Gatineau, and Toronto (source). Its Clutch profile lists Montréal as headquarters, 50 to 249 employees, and a 4.9 rating across 27 reviews (source). Spiria offers application modernization, which it describes as updating legacy systems without disrupting operations, and it states that it takes over projects started by another vendor (source). Spiria also says it is SOC 2 Type 2 certified (source). Clutch lists a minimum project size of $50,000+ (source). Spiria tends to fit Canadian organizations that want a bilingual local partner for both modernization and takeover work.
8. Underlabs
Underlabs Inc. was founded in 2009 and is headquartered in Montréal, 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). Enterprise app modernization makes up 15% of its stated service focus (source). Underlabs tends to fit smaller organizations that want a boutique Montreal team for a focused modernization or mobile project.
Project takeover: when the old vendor is gone
Many Montreal buyers searching for modernization actually need something more urgent first: someone to take over a product a previous vendor abandoned. The goal of a takeover is not a rewrite. It is to get the product stable, understood, and shipping again. A sound takeover follows the same sequence:
- Secure access and ownership. Move the repository, cloud accounts, domains, CI/CD pipelines, and third party credentials under your company's control, and 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.
- Stabilize first. Fix crashes, security holes, and deployment problems before new features.
- Decide per module. Keep what works, refactor what slows you down, and rebuild only what blocks the roadmap.
- Document as you go. The new team should leave the system easier to hand over than they found it.
In this list, Spiria states 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.
Modernization strategies and how engagements are scoped
Most vendors describe the same menu of strategies. Knowing what each one buys you makes proposals easier to compare:
- 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 code to remove technical debt while keeping behavior the same.
- Rebuild. Rewrite modules or the whole product on a modern stack. Highest cost and risk, justified only when the old system blocks the roadmap.
- Replace. Retire custom software in favour of a packaged product such as an ERP, 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, so be wary of a firm that quotes a full rewrite before it has read your code. For background on the strategies, read our application modernization guide, and to benchmark budgets see our breakdown of software developer rates in 2026.
A short buyer guide
- Ask for a case study on your platform. IBM i, mainframe, 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.
- Check where the team sits. Some firms here are Montreal headquartered, others have a Montreal office with delivery elsewhere. Both can work, but ask.
- Verify reviews and certifications yourself. Open the Clutch profile and ask for current compliance documents such as a SOC 2 report.
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 included only firms headquartered in Greater Montreal or with a real Montreal office, and we say which is which in the table. We did not invent ratings, scores, or superlatives for any firm. Percentages and timelines quoted from vendors are their own claims, not independent measurements. 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 or planning a move off an aging stack, see our legacy product transition and project takeover services, or talk to our Montreal team.
Related software guides
- Legacy Software Modernization Companies in Canada
- Legacy Software Modernization Companies
- Custom Software Development Companies in Montreal
- Top IT Companies in Montreal
Related rankings
- Firms with a real Montreal presence that offer legacy modernization include Webisoft, Alithya, CGI, Fresche Solutions, Osedea, Sigma Software, Spiria, and Underlabs. They range from global firms with mainframe tooling to boutique teams. The right choice depends on your platform, the size of the system, and whether you also need a project takeover.
- In this list, Spiria states on its website that it takes over projects started by another vendor, and Webisoft runs a dedicated project takeover service. Other firms may accept inherited codebases too, so ask each one how it scopes the initial code and infrastructure audit.
- Fresche Solutions, launched in Montreal in 1976, describes itself as a global IBM i modernization partner and offers IBM i modernization, managed services, and software. Large integrators such as CGI also handle legacy estates, including mainframes.
- Most organizations are better served by staged modernization. A full rewrite carries the highest cost and risk, and it often loses business rules buried in the old code. Staged approaches, where old and new systems run in parallel, keep the business running and let you stop or adjust if priorities change.
- A local partner can run workshops on site, work in English and French, and overlap fully with your working hours, which helps during cutovers and incidents. Québec organizations often need French documentation and interfaces, which Montreal teams handle as a matter of course.
