No, I did not mean slide transitions, I meant custom slide show (or named slide show). According to Aspose’s version history support of it was added starting from 5.5 but I still can’t find it. See below extract from the history.
I have got your point and regret to share that at present the support for slide show settings is unavailable in Aspose.Slides for .NET at the moment. An issue with ID SLIDESNET-36907 has already been added in our issue tracking system to further investigate the possibility of implementing requested support. This thread has been linked with the issue so that you may be automatically notified once the support will be available.