> ## Documentation Index > Fetch the complete documentation index at: https://docs.kirafin.ai/llms.txt > Use this file to discover all available pages before exploring further. # Pin account to a version > Pin your account to an API version, so you no longer have to send `X-Api-Version` on every call. Send the version you want in `target_version`. The response tells you the version you were on and the one you are on now. Pins only move **forward**. A version older than your current pin is refused. Pinning to the version you are already on is safe and changes nothing. After pinning, `X-Api-Version` is optional. Send it only when you want one request to use a different version — the header still wins over your pin. ## OpenAPI ````yaml /openapi/kira-api.2026-04-14.json post /v1/versioning/upgrade openapi: 3.1.0 info: title: Kira API version: '2026-04-14' description: >- REST API for users, KYC/KYB verification, virtual accounts, payouts, recipients, and webhooks. Every request requires an `x-api-key` header and a bearer access token (see Authentication). Pin your account to version `2026-04-14` before integrating. contact: name: Kira API Support email: support@kirafin.ai servers: - url: https://api.balampay.com description: Production - url: https://api.balampay.com/sandbox description: Sandbox security: - bearerAuth: [] apiKeyAuth: [] tags: - name: Authentication - name: Versioning - name: Users - name: Virtual Accounts - name: Recipients - name: Quotations - name: Payouts - name: Reference paths: /v1/versioning/upgrade: post: tags: - Versioning summary: Pin account to a version description: >- Pin your account to an API version, so you no longer have to send `X-Api-Version` on every call. Send the version you want in `target_version`. The response tells you the version you were on and the one you are on now. Pins only move **forward**. A version older than your current pin is refused. Pinning to the version you are already on is safe and changes nothing. After pinning, `X-Api-Version` is optional. Send it only when you want one request to use a different version — the header still wins over your pin. operationId: post_v1-versioning-upgrade parameters: - in: header name: X-Api-Version required: false description: >- Version applied to this request. It wins over your account's pinned version — see [Versioning](/using-the-api/versioning). schema: type: string example: '2026-04-14' requestBody: required: true content: application/json: schema: type: object required: - target_version properties: target_version: type: string description: >- The version to pin your account to. Use a version this site documents — `2026-04-14` or `2026-06-01`. A version Kira does not support is refused, and so is a version older than your current pin. The error names every version the API accepts. example: '2026-04-14' examples: pin-account: summary: Pin the account value: target_version: '2026-04-14' responses: '200': description: >- Your account is pinned. Both versions come back so you can confirm the move. content: application/json: schema: type: object properties: previous_version: type: string description: >- The version your account was on before this call. An account that was never pinned reports `2025-01-01`. current_version: type: string description: >- The version your account is on now. It equals `target_version`. example: previous_version: '2025-01-01' current_version: '2026-04-14' '400': description: >- The request was refused, and nothing changed on your account. Two things cause it: - The version is not one Kira supports. The message names every version the API accepts. - The version is older than your current pin. The message explains the forward-only rule. content: application/json: schema: type: object properties: statusCode: type: integer description: Always `400`. error: type: string description: Always `Bad Request`. message: type: string description: What is wrong, in words. timestamp: type: string description: When the error happened, ISO 8601. examples: unsupported-version: summary: The version is not supported value: statusCode: 400 error: Bad Request message: >- Unsupported API version '2025-12-01'. Supported: 2026-06-01, 2026-05-28, 2026-04-14, 2025-01-01 timestamp: '2026-09-07T14:11:38.461Z' downgrade: summary: The version is older than your pin value: statusCode: 400 error: Bad Request message: >- Cannot downgrade API version from '2026-05-28' to '2026-04-14'. Upgrades are forward-only. To use an older documented version per-request, send the X-Api-Version header — it is exempt from this rule. timestamp: '2026-09-07T14:11:38.461Z' '401': description: >- Your credentials were not accepted. The message talks about routing, but it is the same body for every cause, so it is not a guide to which one: - The `Authorization` header is missing, expired or wrong. Get a new token from [Get access token](/api-reference/authentication/get-access-token). - The `x-api-key` header is missing or wrong. - One is present and the other is not. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: code: invalid_request message: >- The request could not be matched to a valid route, or was malformed. Verify the path and HTTP method against the API reference. This is a routing or request error, not a credentials or signature problem. security: - bearerAuth: [] apiKeyAuth: [] servers: - url: https://api.balampay.com/sandbox description: Sandbox - url: https://api.balampay.com description: Production components: schemas: ErrorResponse: type: object properties: message: type: string code: type: string statusCode: type: number error: type: string timestamp: type: string path: type: string details: {} required: - message securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- The `data.access_token` value from [Get access token](/api-reference/authentication/get-access-token). apiKeyAuth: type: apiKey in: header name: x-api-key description: API key issued by Kira. ````