> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/buildings-and-infrastructure-portfolio/os-open-linked-identifiers/os-open-linked-identifiers-technical-specification/product-version-information-file-json.md).

# Product Version Information file (JSON)

The OS Open Linked Identifier data package also contains Product Version Information files. These are contained inside each relationship zip package as JavaScript Object Notation (JSON) format.

JSON is an open-standard file and data interchange format that uses human-readable text to store and transmit data objects consisting of attribute-value pairs and array data types.

The general structure of the metadata JSON is detailed below:

## filename

The name of the Linked\_ID CSV file

* **Type**: text
* **Multiplicity**: \[1]

## productPublicationDate

The product publication date.

* **Type**: date
* **Format**: YYYY/MM
* **Multiplicity**: \[1]

## productPublicationName

The Linked\_ID Epoch Number that the JSON file refers to. (In the format “Epoch {number}”.)

* **Type**: text
* **Multiplicity**: \[1]

## Identifier1Source

* **Type**: Object
* **Multiplicity**: \[1]

### Identifier1Source.productName

The product name of the source product for identifier 1.

* **Type**: text
* **Multiplicity**: \[1]

### Identifier1Source.productPublicationDate

The publication date of the source product for identifier 1.

* **Type**: date
* **Format**: YYYY/MM
* **Multiplicity**: \[1]

### Identifier1Source.productPublicationName

The epoch number of the source product for identifier 1. If provided, in the format “Epoch {number}”.

* **Type**: text
* **Multiplicity**: \[0..1]
* **Notes**: Not supplied if null value.

### Identifier1Source.featureType

The feature type of the source for identifier 1. Can be one of:

* BLPU
* Road
* RoadLink
* Street
* TopographicArea
* **Type**: text
* **Multiplicity**: \[1]

### Identifier1Source.identifierType

The identifier type of the source for identifier 1. Can be one of:

* GUID
* TOID
* UPRN
* USRN
* **Type**: text
* **Multiplicity**: \[1]

## Identifier2Source

* **Type**: Object
* **Multiplicity**: \[1]

### Identifier2Source.productName

The product name of the source product for identifier 2.

* **Type**: text
* **Multiplicity**: \[1]

### Identifier2Source.productPublicationDate

The publication date of the source product for identifier 2.

* **Type**: date
* **Format**: YYYY/MM
* **Multiplicity**: \[1]

### Identifier2Source.productPublicationName

The epoch number of the source product for identifier 2. If provided, in the format “Epoch {number}”.

* **Type**: text
* **Multiplicity**: \[0..1]
* **Notes**: Not supplied if null value.

### Identifier2Source.featureType

The feature type of the source for identifier 2. Can be one of:

* BLPU
* Road
* RoadLink
* Street
* TopographicArea
* **Type**: text
* **Multiplicity**: \[1]

### Identifier2Source.identifierType

The identifier type of the source for identifier 2. Can be one of:

* GUID
* TOID
* UPRN
* USRN
* **Type**: text
* **Multiplicity**: \[1]


---

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