Legacy software modernization services

Legacy software modernization, also called application modernization, is changing the stack, architecture or infrastructure of a working application without losing what already works. Typical strategies are replatforming, refactoring and framework upgrades, changing the architecture, replacing a single module and moving infrastructure to code. In our projects under Platform & Cloud Engineering it looked like this:

• Replatforming. For Zeronest we moved the backend that loads and processes data from modems (ETL) from AWS Lambda and DynamoDB to Django and PostgreSQL.
• Framework upgrades. For Enerace we moved to Python 3.13 and Django 5 between April and June 2025, and updated React Native between February and March 2026. For a client in the industrial sector we moved a front end from Vue 2 to Vue 3, from Vuetify 3 to Vuetify 4, and to Vite.
• Infrastructure as code. At Skyfri, Terraform replaced ARM Templates and Azure CLI, and further services received full CI/CD and infrastructure as code.
• Replacing a module. At Skyfri we are building a new IoT system on Azure IoT Hub and IoT Edge, which is meant to replace the current system that collects data from devices.

Which strategy fits depends on the system, so we begin with an audit or a technology discussion.

A modernization starts with an audit of the client's current products and stack. At Skyfri in Oslo we ran a technical audit from 20 November 2023 to 7 January 2024, seven weeks in total. The client asked us to show what to change in the product build process and in performance. The stack at the start of the audit was React, C# and ASP.NET, Python and pyspark, Kusto/ADX, Databricks and Azure.

After the audit, we set the order of changes together with the client. We now work as part of the Skyfri team, next to the colleagues in Oslo.

If you want to scope the work before committing, our free discovery workshops produce a scope, a roadmap and an estimate of cost, time and team composition. They are also the entry point for a modernization.

We change running systems in stages: the development environment first, then production. At Zeronest the new ETL process for modem data was built in September and October 2024. We then switched off the Lambda, the scheduler and DynamoDB first in the development environment and later in production, between December 2024 and April 2025. Updates continued on the live system: the Android target API in August 2025, React Native between April and July 2026, and Django between July and September 2026. As of April 2026 the platform served more than 3,000 prosumer storage installations.

At Skyfri we rebuilt the ETL pipelines in Databricks and ADX, and moved interface components into a shared library instead of implementing each one separately.

The projects behind this page, and what each one shows:

• Skyfri, the solar and battery asset management platform: the audit, infrastructure as code and the new IoT system.
• Zeronest, the solar panel monitoring app with automated battery management: the ETL backend on Django and PostgreSQL.
• Enerace, energy procurement software: the Python and Django upgrades and the React Native update.

The fourth example, the industrial platform we took over, belongs to a client under NDA.

We have 50+ AWS engagements across the company. For cloud migrations we work mainly on AWS with Terraform; see Cloud Application Development for the wider scope.

After a modernization the system can stay with us under an SLA set in the contract, as described under Support & Maintenance. We can provide hypercare after release and agree its scope and duration before the start.

Copyrights pass to you with each payment, and you receive the source code. The working repository stays in our controlled environment. Details on how we handle access and data are on the Security & GDPR page.

For custom software projects our minimum budget is 25,000 EUR. We bill time and material by default and offer a fixed price when the scope is closed; see Custom Software Development. We reply to the contact form within 48 hours on working days.