Modifying the CDT changes will that effect existing instances in production after deploying the CDT changes?

Question

Hi, 
 
 I have added two new columns to the CDT, When I am deploying these changes to production. 
 
 are these two new fields mapped to the existing instances or not ?

Regards, 
 Supriya

Naresh · Answer

Hi, 
 If you add new columns this won't impact in-flight instance as long as certain conditions met 
 
 These columns should accept null values 
 You are not using this new columns in your expression/interface rules to determine some business logic, which will impact on workflow decisions 
 
 The in-flight instance will impact if any of the following changes are done your table 
 
 Deleting columns 
 Changing data type of column 
 Reducing the size of column

Mike Schmitt · Answer

Last I checked, running process instances will continue referring to the version of the CDT that existed when that instance launched. That said, be aware that any subprocesses will be using the new CDT version with added column(s), which you might need to account for in your design.