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summary: "Migration in the Business Central extension lifecycle: generating .delta files with Compare-NAVApplicationObject for conversion to extensions, and moving table and field data between extensions on-premises. It answers questions about delta generation, migration.json, dependency direction, transition extensions and synchronization order."
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---

# Migration

> Migration in the Business Central extension lifecycle: generating .delta files with Compare-NAVApplicationObject for conversion to extensions, and moving table and field data between extensions on-premises. It answers questions about delta generation, migration.json, dependency direction, transition extensions and synchronization order.

Path: [Development](../../development.md) > [Extension lifecycle](../extension-lifecycle.md) > Migration · tier official · system development · narrative reviewed (checked by Opus)

## Overview

This section covers two migration tasks in the extension lifecycle. The first is producing delta files from application object versions, using the Compare-NAVApplicationObject PowerShell cmdlet. The second, in a subtopic, is moving table and field data from a releasing extension to a receiving extension in on-premises Business Central.

Start with the "Generating Delta files" page if you are converting existing application objects to extensions, since the delta output feeds the Txt2Al conversion tool. Go to the subtopic on migrating tables and fields between extensions when data must move from one extension to another. It explains the migration.json file, the direction of the dependency graph, transition extensions and synchronization ordering.

## Key points

- Compare-NAVApplicationObject generates .delta files from application object versions.
- The ExportToNewSyntax flag is required when the deltas will be converted to extensions with the Txt2Al conversion tool.
- The subtopic covers moving table and field data from a releasing extension to a receiving extension.
- Table and field migration between extensions applies to on-premises Business Central.
- The subtopic explains the migration.json file, dependency graph direction, transition extensions and synchronization ordering.
- The subtopic has 4 pages; the hub has 1 own page on delta files.

## Subtopics

- [Migrating tables and fields between extensions (on-premises)](migration/migrating-tables-and-fields-between-exte.md) (4 pages)

## More Learn pages

- [Generating Delta files](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/devenv-generating-delta-files): Description of how to generate delta files with the ExportToNewSyntax flag.

## Videos, posts and code changes

Linked by a Haiku matcher with a grounding quote from the item's summary (link/topics.ts); machine-generated.

- [#10341 Remove Anthropic privacy notice from Expense Agent](../../../../changes/bcapps/10341.md) (code change): "Per-database upgrade attempts to delete the legacy privacy notice"
- [#11822 Added missing indexes for GP historical snapshot](../../../../changes/bcapps/11822.md) (code change): "Added missing indexes to improve query performance during data migration"
- [#12118 Fix Email Inbox retention policy failing on missing indirect Read permission](../../../../changes/bcapps/12118.md) (code change): "Email Inbox retention policy no longer fails due to missing indirect read permission"
- [#12167 Track QuickBooks migration usage consistently](../../../../changes/bcapps/12167.md) (code change): "QuickBooks migration now consistently tracks usage by adding an uptake telemetry event"
- [#9220 Backport SL Migration - Snapshot Project Transactions](../../../../changes/bcapps/9220.md) (code change): "Support for snapshotting and migrating historical Dynamics SL project transactions"
- [#9363 GP - Updates 202607](../../../../changes/bcapps/9363.md) (code change): "The GP migration now spreads item transactions across multiple batches"
- [#9438 SL - Add support for migrating historical project transactions](../../../../changes/bcapps/9438.md) (code change): "A new migration setting enables historical project transactions to be migrated alongside other historical data"
- [#99 Add lifecycle error and privacy knowledge](../../../../changes/bcquality/99.md) (code change): "upgrade phase data writes, install-versus-upgrade dispatch logic, install code dispatch"

Source: Microsoft Learn (CC BY 4.0). Descriptions are Learn's own.