> ## Documentation Index
> Fetch the complete documentation index at: https://docs.alforse.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Supersession & cutover

> How a released Revision or Replacement Part phases over, the cutover fields you tune per item, and how MRP and Get Method honor supersession downstream.

Releasing a **Revision** or **Replacement Part** creates a supersession from the old item to the new item. Configure phase-over behavior with cutover fields on the affected item.

A **Version** edits the existing item and creates no supersession. A **New Part** has no predecessor and also creates none. Only change types that derive a new item from an existing one create supersessions.

NOTE

**Only Revision and Replacement Part supersede.**

The rule is the predecessor: a Revision phases the old revision over to the new one, and a Replacement Part
phases the affected part over to the new number. Version and New Part have no old item to redirect, so release
skips supersession for them entirely.

## Cutover fields

Set these on a Revision or Replacement Part affected item (under **Part Supersession** on the affected item's detail) before you release.

FieldType

<details>
  <summary>**Supersession Mode**required`enum`</summary>

  How planning treats the old item. See the modes below. Defaults to **Consume First**.
</details>

<details>
  <summary>**Discontinuation date**`date`</summary>

  Stop raising purchase orders for the old item after this date. Empty means no planned discontinuation.
</details>

<details>
  <summary>**Successor effectivity**`date`</summary>

  When the successor is used for new demand. Empty means effective immediately at release.
</details>

## Supersession modes

The supersession mode controls how planning handles the old item:

| Mode | Behavior |
| - | - |
| Consume First | Use remaining stock of the old item before switching to the successor. |
| Prefer New | Plan and build with the successor; picking falls back to the old item only while the successor is out of stock. |
| Stock Only | Hold a minimum reserve of the old item for service; no production use. Planning replenishes it only up to that reserve. |
| No Stock | Fully obsolete: do not plan or stock the old item. |

NOTE

**Picking follows the mode too.**

When material is picked for a job, **Consume First** takes the old item until it has no warehouse stock and then the
successor (when the successor is effective and in stock). **Prefer New** and **Stock Only** pick the successor. **No Stock**
skips the old item. Quantities are converted with the item's conversion factor.

## How downstream honors it

On or after the successor-effectivity date, the supersession applies in these places:

* **MRP** records demand that was redirected from the old item to the successor, so planned demand can be shown
  as "redirected from" the old part. The conversion factor sets how many of the successor replace one old part.
* **Picking** resolves the item to pick for each job material by the rules above.
* **Get Method** substitutions on a job material keep the original item as the source, so the substitution is traceable.

HEADS UP

**Release never touches work already in flight.**

Existing stock stays on the old item, and jobs already created keep the exact materials and method version
they were built against. Open documents follow the same rule: a purchase order, sales order, or quote line
that names the old item keeps it; nothing warns or rewrites it at release. Supersession only steers *forward*
planning — a job created after the successor's effectivity date picks up the new item; one created before it
does not shift. That's what makes releasing safe on a busy floor.

## Related

**Reordering & planning**

How the replenishment system and reordering policy read supersession.

[Open](/docs/reference/reordering.md)

**Change types**

Which change types write a supersession (Revision and Replacement Part), and which don't.

[Open](/docs/reference/change-orders/change-types.md)


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