If you linked one or more external isCOBOL SDK to the IDE, you can choose which one to use for the current project. Select isCOBOL Settings > Installed isCOBOL in order to get the list of available SDKs and check the one you wish to use.

See Binding additional isCOBOL SDK for more information about how to add external isCOBOL SDKs to the IDE.