improve v10 spec

1 files changed, 8 insertions, 3 deletions

diff --git a/core/api-merchant.rst b/core/api-merchant.rst
index ca0cd351..00e4a7f6 100644
--- a/core/api-merchant.rst
+++ b/core/api-merchant.rst
@@ -2762,9 +2762,14 @@ to validate that a customer made a payment.
       // Will match the ``faketime`` argument of the
       // query if one was present, otherwise the current
       // time at the backend.
-      otp_timestamp?: Integer;
+      //
+      // Available since protocol **v10**.
+      otp_timestamp: Integer;
 
-      // Current OTP code of the device.
+      // Current OTP confirmation string of the device.
+      // Matches exactly the string that would be returned
+      // as part of a payment confirmation for the given
+      // amount and time (so may contain multiple OTP codes).
       //
       // If the ``otp_algorithm`` is time-based, the code is
       // returned for the current time, or for the ``faketime``
@@ -2784,7 +2789,7 @@ to validate that a customer made a payment.
       // ``otp_algorithm`` and matching client query arguments.
       //
       // Available since protocol **v10**.
-      otp_code?: Integer;
+      otp_code?: String;
 
    }