Hi alca_3047856 ,
Seems like your BTSDK version is old and example you are trying is higher version .
Please update the wiced_btsdk version and try [ Delete old wiced_btsdk libraries -> Click New Application -> select a kit name -> wiced_btsdk -> create ]?
CYW20721 is not a product supported within the broad market , thus in community. So please contact your local Cypress sales/FAE team to discuss further queries specific to 20721.