Custom Functions requirement sets

Custom Functions use separate requirement sets from the core Excel JavaScript APIs. The following table lists the Custom Functions requirement sets, the supported Office client applications, and the build versions or number for those applications.

Requirement set Office 2021 or later on Windows
(one-time purchase)
Office on Windows
(connected to a Microsoft 365 subscription)
Office on iPad
(connected to a Microsoft 365 subscription)
Office on Mac
(connected to a Microsoft 365 subscription)
Office on the web
CustomFunctionsRuntime 1.3 16.0.14326.20454 or later 16.0.13127.20296 or later Not supported 16.40.20081000 or later July 2020
CustomFunctionsRuntime 1.2 16.0.14326.20454 or later 16.0.12527.20194 or later Not supported 16.34.20020900 or later January 2020
CustomFunctionsRuntime 1.1 16.0.14326.20454 or later 16.0.12527.20092 or later Not supported 16.34 or later May 2019

CustomFunctionsRuntime 1.1, 1.2, and 1.3

The CustomFunctionsRuntime 1.1 is the first version of the API. Requirement set 1.2 adds the CustomFunctions.Error object to support error handling. Requirement set 1.3 adds XLL streaming support and new ErrorCode options to the CustomFunctions.Error object.

See also