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Legacy system modernization for the system too old to touch.

Modernize the application your business depends on, one module at a time. We review the existing code and data, plan integrations and run old and new systems alongside each other where practical. Data reconciliation, rollback planning and your team’s approval guide each release.

Discuss your projectSee what we replace
  • A free 5-day audit comes first
  • We sign an NDA before we see anything
  • Old and new run side by side
  • You own all the code

Don't take our word for it. Ask AI about this service:

Module replacement

Example

Module 2 of 5: customer accounts

  1. Copied 9,300 accounts from the old database
  2. Ran old and new side by side for three weeks
  3. Balances matched on all but 2 accounts

  4. 2 balances differ. Send them to your accounts team before the switch?

An example with made-up figures. The buttons send nothing.

How legacy modernization works.

  1. We map the old system

    We sit with the people who use it and write down what every screen, report and workaround does, including the parts nobody documented.

  2. We replace one module

    We rebuild one part, such as orders or stock, and copy its records across. Old and new run side by side until the figures match.

  3. Your team switches over

    People move to the new module only when your IT team approves. Then the next module starts, and the old system shrinks piece by piece.

Legacy systems we modernize.

Start with the system everyone works around. Each tab shows a part of it as it runs today and what changes once that part is replaced.

  • Today

    The software only runs on a few old machines

    Once replaced

    Old desktop software rebuilt, one part at a time

    We rebuild the program your business depends on module by module, so staff never lose a working day to the move. Each new part runs next to the old one until your team trusts it.

    Side by sideuntil the figures match

    Start a project
  • Today

    Nobody left knows how the database works

    Once replaced

    Every record moved, counted and checked

    Years of customers, orders and stock move into a database your IT team can support. We count every record on both sides and trace any difference before anyone relies on the new system.

    Every recordchecked against the old system

    Start a project
  • Today

    A spreadsheet quietly became the system

    Once replaced

    The spreadsheet turned into proper software

    The workbook that runs pricing, scheduling or stock becomes software with one set of figures, logins and a record of who changed what. The formulas your team trusts are kept and written down.

    One versionof the figures, not a copy on every desk

    Start a project
  • Today

    The old system cannot talk to anything new

    Once replaced

    New modules that share data with the rest

    While the move is under way, old and new exchange data so nobody types anything twice. Once it is done, the new system connects to your ERP, CRM, apps and reports.

    Connectedto the systems you add next

    Start a project

How you stay in control.

Touching the system your business runs on carries real risk, so every modernization we take on follows these four rules.

  • No switch without a yes

    Each new module runs next to the old one until the figures match. People move across only when the person you name approves it.

    • You choose who approves each switch
    • Every difference in the figures flagged
    • Every switch has a rollback plan

  • No record left behind

    We copy, count and check every record against the old system before anyone relies on the new one. Your data stays in your own cloud account.

    • Every record counted on both sides
    • Migrated data lands in your cloud account
    • NDA, MSA and DPA cover the migration

  • The rest keeps running

    Parts not yet replaced work as they do today, and old and new share data during the move. We use tools your IT team knows and document the system as we go.

    • Old and new connected during the move
    • What the old system did, written down
    • New code and database in your name

  • You see the figures agree

    Record counts and totals from the old and new systems sit next to each other, with every difference listed. You switch when the two columns agree, and you can see that they do.

    • Old and new compared, side by side
    • Every difference logged until it is fixed
    • Spend shown against the fixed price

Modernization project timeline.

No stage commits you to the next one. In week three your own records are already sitting in the new module.

  1. Week 1

    Audit

    We sit with the people who use the old system, map what each part does and pick the module that is safest to replace first.

    You end withA plan and a fixed price.

  2. Weeks 2 to 3

    Copy

    We copy that module's records into a first working version and check every count and total against the old system.

    You end withProof the data moves cleanly, or a clear no.

  3. Weeks 4 to 8

    Build

    We build the module in full, with a working demo every week, connected to the parts of the old system that stay.

    You end withA module your IT team has signed off.

  4. Weeks 9 to 10

    Side by side

    Old and new run together on real work until the figures match. Your team switches when the person you named says yes.

    You end withOne module replaced, and a plan for the next.

After the first module we move to the next the same way, until you can switch the old system off. Or we hand over to your team with full documentation.

Start with a free first step.

Show us the system everyone is afraid to touch. On day five you have a map of what it really does, the module to replace first and a fixed price, before anyone changes a line.

Discuss your project

What you hold when it ends

Free, 5 days

  • A map of what the old system does, including the undocumented parts
  • The module that is safest to replace first
  • A fixed price and a timeline for it

The map of your old system is yours, even if someone else does the replacing.

What our clients say.

From clients in the US, Portugal, New Zealand and the UK.

  • I am delighted with them. Such a catch!

    Read the full quote from Software project client

    Being associated with iTechnoSol was a pleasant and satisfying experience. They are good at many things, but I can't forget these two things in particular - their speed of response and clear understanding of my ideas. The team is really talented and was always available to answer my questions and to provide feedback. They beautifully nurtured the project and delivered it accordingly. I am delighted with them. Such a catch!

    Software project clientUnited States

  • They are talented and attentive.

    Read the full quote from Mobile app client

    For iTechnoSol, there is only one word in my mind - Fantastic! I am not just impressed by their service quality, but also for their working strategies. I am never going to regret my decision to hire them for the development of my mobile application. They have really made me happy by delivering an exceptional solution and extraordinary web design. They are talented and attentive. Most importantly, THEY CARE about client needs. Highly recommended.

    Mobile app clientUnited States

  • I am looking forward to giving my future projects to iTechnoSol again.

    Read the full quote from Web app redesign client

    I already had a web application, but it was not up to the mark. So, I gave that project to iTechnoSol and told them that they are free to do anything, just give me a trendy but user-friendly app. I thought that redesigning existing projects is quite tough as the teams have to mold their thought processes according to my comfort zone, but I must say that they left no loophole in their work and offered a design that is a treat to the eyes! I am looking forward to giving my future projects to iTechnoSol again.

    Web app redesign clientPortugal

  • And yes, they have kept their promise.

    Read the full quote from Customer self-service software client

    We needed user-friendly software for customers so that they can get easy access to our services even without any admin support. When we discussed the project with iTechnoSol, they understood our ideas of business in detail and promised to deliver what we wanted. And yes, they have kept their promise. Keep up the good work, iTechnoSol. We hope we meet again soon for other projects shortly.

    Customer self-service software clientNew Zealand

  • iTechnoSol stood behind us like a rock!

    Read the full quote from Outsourcing client, four-person team

    We are a team of four people who dream big and take a lot of projects altogether. So, we often need to outsource some of our software projects. We came to know about iTechnoSol from one of our clients, and we approached them. Within a day or two, they arranged an enthusiastic and dedicated development team through their software consultancy services! That project was big and very important for us, and we must say iTechnoSol stood behind us like a rock! Thank you buddies for all your love and support. We highly recommend this software company.

    Outsourcing client, four-person teamUnited Kingdom

Legacy modernization questions.

What it costs, how your data stays whole and how the business keeps running during the move.

What information helps you assess a legacy system?

Share the technology stack, critical workflows, integrations, available documentation and known failures. Identify data that must be retained and acceptable maintenance windows. An initial assessment establishes whether to improve, replace or retain each part before committing to a migration plan.

How much does legacy system modernization cost?

The price moves with the size of the old system, how many modules it has, how clean its data is and how much of it nobody documented. The free 5-day audit ends with a fixed price for the first module, and you can stop there with the plan in hand.

Will our people have to stop work during the move?

No. We replace one module at a time and the old system keeps running until the new one matches it. People switch only when the figures agree and your IT team approves.

How do you make sure no data is lost?

We copy every record, count it on both sides and compare the totals with the old system before anyone relies on the new one. Old and new run side by side on real work, and we trace and fix any difference before the switch.

What if nobody knows how the old system works anymore?

That is common. We work it out from the screens, the reports, the data and the people who use it every day, and write it down as we go. You end up with documentation the old system never had.

Who owns the new system once it is built?

You own it from day one: the new code, the database with every migrated record and the write-up of what the old system did, all in accounts under your name. If we part ways you keep everything and owe nothing extra.

How do we work with a team based in India?

Your first call is with a founder. We overlap 3 to 4 hours with US and UK working hours, report in the tools your IT team already uses and reply within 4 business hours.

See all questions

Related projects.

Each one shows what the client needed, what we built and the result, so you can judge how close it is to your own project.

From the blog.

Plain-language notes from our engineers on this kind of work, written for the owner who signs the check.

Free project estimate

Start your modernization project.

Walk a founder through the old system on a 30-minute call. You leave knowing which module we would move first, roughly what it would cost and how your team keeps working meanwhile. If replacing it is the wrong move, we say so.

What you get back

  • An indicative budget range
  • A realistic timeline
  • What moves the cost up or down
  • A reply within 4 business hours
  • Answered by a founder
  • NDA on request, before you share details

Don't take our word for it

Ask your AI about this service.

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