Antya updesh (antya = final) is the term used for the last or final teaching/sermon given by a Tirthankar before Nirvana. In Jain tradition, this final instruction sums up the essential dharma that the Tirthankar leaves for his followers. If you want, I can explain how this concept is described in specific Jain texts and how it is viewed in Digambar and Shwetambar traditions.