Get (one or more) invoice by Invoice Number

Hi @abitamaspp apologies for the long delay. If this is still an issue for you have you tried invoice_numbers?
From the SDK:
def get_invoices(
        self,
        xero_tenant_id,
        if_modified_since=empty,
        where=empty,
        order=empty,
        i_ds=empty,
        invoice_numbers=empty,
        contact_i_ds=empty,
        statuses=empty,
        page=empty,
        include_archived=empty,
        created_by_my_app=empty,
        unitdp=empty,
        summary_only=empty,
        _return_http_data_only=True,
        _preload_content=True,
        _request_timeout=None,
    ):
        """Retrieves sales invoices or purchase bills  # noqa: E501
        OAuth2 scope: accounting.transactions, accounting.transactions.read
        :param str xero_tenant_id: Xero identifier for Tenant (required)
        :param datetime if_modified_since: Only records created or modified since this timestamp will be returned
        :param str where: Filter by an any element
        :param str order: Order by an any element
        :param list[str] i_ds: Filter by a comma-separated list of InvoicesIDs.
        :param list[str] invoice_numbers: Filter by a comma-separated list of InvoiceNumbers.
        :param list[str] contact_i_ds: Filter by a comma-separated list of ContactIDs.
        :param list[str] statuses: Filter by a comma-separated list Statuses. For faster response times we recommend using these explicit parameters instead of passing OR conditions into the Where filter.
        :param int page: e.g. page=1 – Up to 100 invoices will be returned in a single API call with line items shown for each invoice
        :param bool include_archived: e.g. includeArchived=true - Invoices with a status of ARCHIVED will be included in the response
        :param bool created_by_my_app: When set to true you'll only retrieve Invoices created by your app
        :param int unitdp: e.g. unitdp=4 – (Unit Decimal Places) You can opt in to use four decimal places for unit amounts
        :param bool summary_only: Use summaryOnly=true in GET Contacts and Invoices endpoint to retrieve a smaller version of the response object. This returns only lightweight fields, excluding computation-heavy fields from the response, making the API calls quick and efficient.
        :param bool _return_http_data_only: return received data only
        :param bool _preload_content: load received data in models
        :param bool _request_timeout: maximum wait time for response
        :return: Invoices
        """

        # verify the required parameter 'xero_tenant_id' is set
        if xero_tenant_id is None:
            raise ValueError(
                "Missing the required parameter `xero_tenant_id` "
                "when calling `get_invoices`"
            )

        collection_formats = {
            "IDs": "csv",
            "InvoiceNumbers": "csv",
            "ContactIDs": "csv",
            "Statuses": "csv",
        }
        path_params = {}

        query_params = []

        if where is not empty:
            query_params.append(("where", where))

        if order is not empty:
            query_params.append(("order", order))

        if i_ds is not empty:
            query_params.append(("IDs", i_ds))

        if invoice_numbers is not empty:
            query_params.append(("InvoiceNumbers", invoice_numbers))

        if contact_i_ds is not empty:
            query_params.append(("ContactIDs", contact_i_ds))

        if statuses is not empty:
            query_params.append(("Statuses", statuses))

        if page is not empty:
            query_params.append(("page", page))

        if include_archived is not empty:
            query_params.append(("includeArchived", include_archived))

        if created_by_my_app is not empty:
            query_params.append(("createdByMyApp", created_by_my_app))

        if unitdp is not empty:
            query_params.append(("unitdp", unitdp))

        if summary_only is not empty:
            query_params.append(("summaryOnly", summary_only))

        header_params = {
            "xero-tenant-id": xero_tenant_id,
        }

        if if_modified_since is not empty:
            header_params["If-Modified-Since"] = if_modified_since

        local_var_files = {}
        form_params = []

        body_params = None
        # HTTP header `Accept`
        header_params["Accept"] = self.api_client.select_header_accept(
            ["application/json"]
        )

        # Authentication setting
        auth_settings = ["OAuth2"]
        url = self.get_resource_url("/Invoices")

        try:
            return self.api_client.call_api(
                url,
                "GET",
                path_params,
                query_params,
                header_params,
                body=body_params,
                post_params=form_params,
                files=local_var_files,
                response_type="Invoices",
                response_model_finder=self.get_model_finder(),
                auth_settings=auth_settings,
                _return_http_data_only=_return_http_data_only,
                _preload_content=_preload_content,
                _request_timeout=_request_timeout,
                collection_formats=collection_formats,
            )
        except exceptions.HTTPStatusException as error:
            raise translate_status_exception(error, self, "get_invoices")
XeroAPI / xero-python-oauth2-app

Get (one or more) invoice by Invoice Number #34
