If previous processes are not yet completed if you change existing CDT(Adding ad

@shanmukhaprasads Adding an extra input to the interface (the SAIL expression rule) is NOT an issue to the best of my knowledge. That completely depends on the way you pass the arguments to the SAIL interface. If you pass the arguments to the interface by keyword(https://forum.appian.com/suite/help/16.1/Expressions.html#By_Keyword), adding an extra parameter isn't an issue. In this case, the user won't see any error messages. But at the same time if you pass the arguments to the interface by position (as specified at https://forum.appian.com/suite/help/16.1/Expressions.html#By_Position) this creates an issue by breaking the tasks in old process instances.

Process upgrade comes into picture when the tasks in the older process instances break because of the extra parameter added in case when the interface is being passed the arguments via position.

And re additional columns, as long as you develop the interface in such a way that it won't try to access the newly added columns in older instances(for instance using index() or property(), controlling the behaviour of interface based on the a date and time value which indicates the newly added changes), then this shouldn't be an issue.

@shanmukhaprasads Adding an extra input to the interface (the SAIL expression rule) is NOT an issue to the best of my knowledge. That completely depends on the way you pass the arguments to the SAIL interface. If you pass the arguments to the interface by keyword(https://forum.appian.com/suite/help/16.1/Expressions.html#By_Keyword), adding an extra parameter isn't an issue. In this case, the user won't see any error messages. But at the same time if you pass the arguments to the interface by position (as specified at https://forum.appian.com/suite/help/16.1/Expressions.html#By_Position) this creates an issue by breaking the tasks in old process instances.

Process upgrade comes into picture when the tasks in the older process instances break because of the extra parameter added in case when the interface is being passed the arguments via position.

And re additional columns, as long as you develop the interface in such a way that it won't try to access the newly added columns in older instances(for instance using index() or property(), controlling the behaviour of interface based on the a date and time value which indicates the newly added changes), then this shouldn't be an issue.