Modernising a Legacy .NET Platform Without Stopping Delivery

For our July meet-up, we will be welcoming Kseniia Korostelova, who will be delivering a talk on Modernising a Legacy .NET Platform Without Stopping Delivery

Modernizing legacy systems sounds exciting in architecture diagrams. But reality is usually much messier.

Tightly coupled services, shared databases, hidden dependencies, operational risk, delivery pressure, and years of accumulated technical debt make large-scale modernization far more complex than simply “moving to microservices” or “upgrading to .NET Core”.

In this talk, I’ll share lessons learned from modernizing a large-scale .NET platform operating in a high-throughput, highly regulated environment serving millions of users and processing thousands of transactions per second — all while continuing to deliver features and support live production workloads.

Rather than a big-bang rewrite, we adopted an incremental modernization strategy:

modernizing APIs and service boundaries,
extracting selected capabilities into dedicated services,
introducing orchestration layers,
and progressively migrating parts of the platform from .NET Framework to .NET Core.

I’ll cover both the technical and organizational realities of the journey:

what worked well,
what became unexpectedly difficult,
where microservices helped,
where they introduced new complexity,
and why modernization is often more about managing risk and dependencies than technology itself.

This session is not a step-by-step migration tutorial.

It is a practical, experience-driven look at how engineering teams evolve large legacy systems at scale without pausing delivery, disrupting production, or rewriting everything from scratch.

Food

We have a selection of food available including Vegan options but if you'd like to know more please drop one of our organisers a message before the event via the group message forum. (https://secure.meetup.com/messages/)

If you would need assistance to leave the building in the event of an evacuation then please let us know via the group message forum. (https://secure.meetup.com/messages/)

Schedule

Doors open from 18:00
Pizza at 18:20
Intro and welcome 18:40
Speaker Starts 19:00

Close ~21:00 (Don't feel bad if you have to leave early for a train/bus/lift home - no one will be offended)

Live Steam Link
https://youtube.com/live/SO1jaR-hJ_A?feature=share

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Travel

http://dotnetliverpool.org.uk/how-to-find-us

Train - James Street station is a 10 minute walk from the Lab. Liverpool Lime Street is approx 15-20 minutes walking distance.

Driving - Underground parking available at Liverpool One.