# Create or update items in ClientList
Use this format to create/update items in the client list. The filename should contain ClientList and format is xls(x)
The following columns can be defined:
- ClientID / ExternalID
- ClientCode (required)
- ClientName
- ... additional columns are mapped on the client list column names
If ClientID/ExternalID is specified, the ExternalID column will be used to find the existing client in the clients list. If not found, a new listitem is created.
If ClientName is not specified the clientname and title are not updated.
To update the ClientCode with a new value, specify the original value in the ClientCode column and add a column with the name __Code__ and the new ClientCode. If a ClientID/ExternalID column is used, the ClientCode is always updated with the specified value and never used to search for an existing listitem.
To update the ExternalID with a new value, specify the ClientCode value in the ClientCode column and add a column with the name __ExternalID__ and the new ExternalID value. Leave the ClientID/ExternalID empty!