bcquality/microsoft/knowledge/breaking-changes/obsolete-table-fields-instead-of-deleting-them.md
Jesper Schulz-Wedde 2b5550c346
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Improve partner onboarding and documentation navigation (#174)
Lead with a complete plugin quick start and add task-oriented usage, troubleshooting, customization, and contribution guides. Preserve the broader plugin framing, correct conflicting contract guidance, support Agents folder reviews, and align repository validation. Convert existing sample references to clickable links without changing knowledge rules.

Co-authored-by: Jesper Schulz-Wedde <jesper.schulzwedde@microsoft.com>
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
2026-09-09 17:31:03 +02:00

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---
bc-version: [all]
domain: breaking-changes
keywords: [table-field, obsoletestate, obsoletereason, obsoletetag, pending, removed, data-loss]
technologies: [al]
countries: [w1]
application-area: [all]
---
# Obsolete published table fields instead of deleting, renaming, or renumbering them
## Description
A shipped table field carries both a source-level contract and persisted data. Renaming a field while retaining its ID is prohibited by AppSourceCop AS0005 and can break dependent extensions, but it is not inherently a drop-and-readd operation and should not be described as automatic data loss. Deleting the field or replacing it under a different ID is the data-loss risk: the old field storage is no longer represented unless data is migrated. The supported path is to keep the old field and obsolete it, add a replacement under a new ID, and migrate values before later removal.
## Best Practice
Keep the old field's ID, name, and type unchanged. Add the replacement as a separate field under an unused ID, then mark the old field `ObsoleteState = Pending` with an `ObsoleteReason` that names the replacement and an `ObsoleteTag` recording the obsoletion version. Keep the old field readable so an upgrade codeunit can copy its data during the deprecation window. Move it to `ObsoleteState = Removed` only in a later release, after the window has passed and data has migrated.
See sample: [`obsolete-table-fields-instead-of-deleting-them.good.al`](obsolete-table-fields-instead-of-deleting-them.good.al).
## Anti Pattern
Renaming published `Email` to `Contact Email` with the same ID violates the compatibility contract and AS0005, even though the retained ID does not itself imply a fresh empty column. Deleting `Email` or changing its ID additionally risks losing its stored values. Detection: any previously shipped field whose name changes at the same ID, or whose original ID disappears without the unchanged field being retained as `Pending` and its data migrated to a separate replacement field.
See sample: [`obsolete-table-fields-instead-of-deleting-them.bad.al`](obsolete-table-fields-instead-of-deleting-them.bad.al).