How to change a script task version in SSIS?
I believe I have the same issue, and here is the work around that got over my issue. 

Details first: 


I have sql server 2016 (13.0.4411.0)
SSISDB has the schema version (13.0.1601.5)
I am using an integration services package created in visual studio
The script component (Which states it is 2015 C#) has the path:
C:\Program Files (x86)\Microsoft SQL
Server\130\DTS\Binn\VSTA14_IS_ST_CS_Template.vstax


If I deploy to the catalog through SSMS, it won't let me execute the package through the integration services catalog (due to the message experienced by Zach - version 15.0 not supported).

The workaround: 

If I deploy the package through Visual Studio to the 'Integration Services Catalog' on the required instance, this message goes away and the project runs successfully. This is not ideal as we should be able to deploy through SSMS, but meant that the project can progress.