diff --git a/docs/build/html/_sources/oracles.txt b/docs/build/html/_sources/oracles.txt
index 641cadb3b1..63f2f8fef2 100644
--- a/docs/build/html/_sources/oracles.txt
+++ b/docs/build/html/_sources/oracles.txt
@@ -104,7 +104,7 @@ Here is an extract from the ``NodeInterestRates.Oracle`` class and supporting ty
 .. sourcecode:: kotlin
 
    /** A [FixOf] identifies the question side of a fix: what day, tenor and type of fix ("LIBOR", "EURIBOR" etc) */
-   data class FixOf(val name: String, val forDay: LocalDate, val ofTenor: Duration)
+   data class FixOf(val name: String, val forDay: LocalDate, val ofTenor: Tenor)
 
    /** A [Fix] represents a named interest rate, on a given day, for a given duration. It can be embedded in a tx. */
    data class Fix(val of: FixOf, val value: BigDecimal) : CommandData
diff --git a/docs/source/oracles.rst b/docs/source/oracles.rst
index 641cadb3b1..63f2f8fef2 100644
--- a/docs/source/oracles.rst
+++ b/docs/source/oracles.rst
@@ -104,7 +104,7 @@ Here is an extract from the ``NodeInterestRates.Oracle`` class and supporting ty
 .. sourcecode:: kotlin
 
    /** A [FixOf] identifies the question side of a fix: what day, tenor and type of fix ("LIBOR", "EURIBOR" etc) */
-   data class FixOf(val name: String, val forDay: LocalDate, val ofTenor: Duration)
+   data class FixOf(val name: String, val forDay: LocalDate, val ofTenor: Tenor)
 
    /** A [Fix] represents a named interest rate, on a given day, for a given duration. It can be embedded in a tx. */
    data class Fix(val of: FixOf, val value: BigDecimal) : CommandData