pmpro_twocheckout_return_url_parameters

For TwoCheckout only. Add additional parameteres to the TwoCheckout checkout URL in the form of an array of arrays of name-value pairs with the format array('name' => 'value').

apply_filters( 'pmpro_twocheckout_return_url_parameters', array() );

pmpro_twocheckout_ptpstr

For TwoCheckout only. Modifies the entire query string passed to the TwoCheckout checkout URL.

apply_filters( 'pmpro_twocheckout_ptpstr', string $ptpStr, MemberOrder $order );