.NET & C# Modernization at Enterprise Scale
Automate .NET version upgrades, code quality remediation, and dependency management across your entire C# portfolio safely, consistently, and without pulling engineers off product work.
.NET 8 and .NET 9 both reach end of life November 2026.
Every codebase on either version must migrate to .NET 10. Starting now, a major .NET version goes out of support every November so teams that don't build a repeatable migration path will face this problem every year. Manual, repo-by-repo migration won't keep pace.
Why .NET modernization breaks down at scale
Migrating hundreds of .NET repositories to .NET 10 would have cost us hundreds of engineering hours. With Moderne, we did it at a scale and speed that simply wouldn’t have been possible otherwise.
C# and .NET are foundational across financial services, healthcare, government, and enterprise but the scale that makes .NET so embedded is exactly what makes keeping it current so hard.
- Multiple .NET versions across repositories create fragmentation and inconsistent security baselines
- A .NET 6-to-10 migration traverses four major versions, each with API removals, renames, and behavioral changes that compound
- Every
Microsoft.AspNetCore.*,EntityFrameworkCore.*, andExtensions.*package requires version-locked NuGet upgrades - Manual migration means reading 50+ pages of breaking-change documentation per version, then hand-applying each fix across every repository
- Human reviewers miss edge cases — and changes with behavioral implications require a decision, not just automation
Manual, repository-by-repository migration doesn't scale. What should be routine maintenance becomes a coordination problem that stalls for quarters.
Enterprise .NET teams need more than version bumps.
A modernization tool must support safe, coordinated transformation at portfolio scale across hundreds of repositories, multiple framework versions, and varying team ownership.
Semantic correctness
Understands program intent — not just syntax — so changes are safe and accurate across the entire codebase.
Multi-repository orchestration
Coordinates changes across hundreds of repositories without manual sequencing or coordination overhead.
NuGet and dependency management
Updates .csproj project files, NuGet packages, and transitive dependencies automatically across the portfolio.
Style and formatting preservation
Maintains existing formatting and coding conventions so changes integrate cleanly without diff noise.
Human-in-the-loop for behavioral changes
Flags changes requiring judgment rather than applying them blindly — automated wins ship immediately, decisions get surfaced.
Portfolio-wide visibility
Provides insight into migration progress, coverage, and risk across the full application portfolio — not just individual repositories.
On-demand webinar
Automated Code Changes at Scale
Engineers from Netflix, Airbnb, and LinkedIn share how they tackle automated code changes at scale — and get developers to actually review and merge the PRs.
The .NET modernization platform built for enterprise scale
Moderne operates on a Lossless Semantic Tree (LST), a compiler-accurate structural model of your codebase that enables deterministic transformations across repositories.
Migrate to .NET 10 across your entire portfolio
- Run UpgradeToDotNet10 once and it chains through every intermediate version automatically
- Transformations with clear targets apply automatically.
- Changes requiring human judgment are flagged with inline markers so your team decides before anything runs.
Remediate code quality across the codebase
- Style: file-scoped namespaces, pattern matching, nameof, expression-bodied members
- Performance: StringBuilder chains, CancellationToken propagation, accidental boxing
- Simplification: boolean literal comparisons, null-coalescing chains, over-specified lambdas
- Redundancy: unused declarations, redundant casts, unnecessary async/await wrappers
Manage NuGet dependencies at portfolio scale
- Parse and transform .csproj files to upgrade NuGet packages and update project references across entire repository estates
- Extend governance beyond application code to the underlying dependency layer
Enforce consistent standards across teams
- Apply the same transformation across every repository in your portfolio
- Naming conventions, formatting standards, and migration patterns run identically whether a repository has 10 files or 10,000
- No manual coordination or per-team variation
Enable coding agents to work safely at scale
- C# is now fully represented in the OpenRewrite LST, giving coding agents a semantic model of your .NET codebase
- Recipes provide the governed execution layer that applies agent-proposed changes safely and consistently across repositories
Comprehensive C# recipe coverage
Every C# recipe operates on the Lossless Semantic Tree, giving you deterministic, format-preserving transformations across version migration, code quality, and test framework modernization.
Code Quality
Style, simplification, performance, redundancy, LINQ, formatting, and naming. Validated against Roslynator and Meziantou diagnostics on real open source repositories.
.NET Migration
Full migration coverage from .NET Core 1.0 through .NET 10, including ASP.NET Framework to Core, NuGet upgrades, obsolete API replacement, and breaking change detection.
Test Framework Migration
Complete xUnit to TUnit migration path: attribute mapping, lifecycle conversion, assertion rewriting, and dependency updates.
Moderne vs other .NET Migration approaches
Organizations evaluating .NET modernization typically start with Microsoft's own tooling, but most approaches fall short at portfolio scale.
Moderne
Enterprise-scale orchestration
Applies validated recipes across hundres of repositories in a single run with impact analysis, coordinated PRs, and centralized progress tracking.
Semantic correctness
Lossless Semantic Trees deliver deterministic, format-preserving transformations. Changes are accurate and reviewable without fragile regex matches or string replacements.
Two-tier migration model
Automated fixes apply immediately. Changes requiring human judgment are flagged with inline markers — automated wins now, prioritized decisions surfaced, not buried.
Portfolio-wide upgrade control
Coordinates .NET migrations across teams and repositories with controlled rollouts and full visibility into progress and coverage.
Coding agent-ready
C# is fully represented in the LST, giving coding agents a semantic model of your .NET codebase to reason over and operate against safely.
.NET Upgrade Assistant
Repo-by-repo execution
Guides developers through individual project migrations manually. Does not coordinate across hundreds of repositories or generate reviewable PRs at scale.
Not supported beyond .NET 9
Microsoft's tool does not extend to .NET 10 migration coverage, leaving teams without tooling support for the most critical upcoming upgrade.
Roslyn Analyzers
Compiler-level C# analysis widely used for diagnostics and small-scale fixes. Not designed for coordinated, multi-repository transformation at enterprise scale. Moderne's recipes are built on the same Roslynator and Meziantou diagnostic standards, but execute them deterministically across your entire portfolio.
Frequently Asked Questions
