KB HDI How to migrate Legacy specific Activities to .net6 projects - rpapub/WatchfulAnvil GitHub Wiki

How Do I Migrate Legacy UiPath Activities Like MultipleAssign to Modern .NET 6 Projects?

Overview

This guide explains how to identify, handle, and replace legacy-only activities—such as MultipleAssign from UiPath.System.Activities.Runtime.Windows—when migrating UiPath workflows from the legacy .NET Framework to the modern .NET 6 Windows compatibility mode.

These legacy activities are often no longer editable or supported in modern projects and must be replaced with modern equivalents.

Prerequisites

  • UiPath Studio 24.10+ installed
  • A project migrated or created with "targetFramework": "Windows" in project.json
  • Basic understanding of .xaml file structure
  • Awareness of project.json dependency management

Steps

  1. Open the Legacy Workflow

    • Open your original .NET Framework 4.6.1-based project in UiPath Studio.
    • Locate any legacy activities (e.g., MultipleAssign, CommentOut, etc.).

  2. Identify Legacy-only Activities

    • Look for activities with these symptoms:
      • Cannot be edited after migration
      • Appear with a faded UI or missing editor
    • Check the activity namespace:
      • UiPath.System.Activities.Runtime.Windows = legacy-only

  3. Check Dependency Conflicts

    • Open project.json and note the version of: 
      "UiPath.System.Activities.Runtime": "24.x.x"
    • If you receive a dependency downgrade popup, accept the upgrade to align with the required modern version (e.g., 25.2.4).

  4. Replace with Modern Equivalents

    • For MultipleAssign, replace it with individual Assign activities.
    • Remove any unsupported containers like CommentOut.
    • Use UiPath.System.Activities versions only.

  5. Test Your Workflows

    • Run affected test cases.
    • Validate that outputs, variable values, and workflow logic remain correct.

Expected Outcome

  • Legacy-only activities like MultipleAssign are successfully replaced with editable, modern equivalents.
  • Your project builds and runs cleanly under .NET 6.
  • No broken or uneditable activities remain in the designer.

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