Code Fix: Cannot inherit from DocuSign SmartObject dll assembly to override methods

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Issue Description

You cannot inherit the properties and methods of the DocuSign SmartObject dll assembly in a Visual Studio custom project. You are presented with an error.

Error Message

The following error occurs: “CS0509: 'ExtendDoc': cannot derive from sealed type 'Broker”


The assembly was marked as sealed, therefore inheritance was not allowed.


  1. Ensure you have K2 Five RTM installed.
  2. Get the K2 Five RTM FP20 from Regional Support.
  3. Install the K2 Five RTM FP20 to apply the fix.
  4. You are no longer presented with an error.