As Internet of Things advances, various smart objects and services permeate in our living environment. Due to their dynamic join/leave behaviors, service discovery protocols (SDPs) have been proposed. As new SDPs are introduced and legacy SDPs evolve, the incompatible islands of smart objects inevitably arise. To solve this issue, many research works are presented, but they cannot accommodate a new protocol or a new version of the legacy protocol. To solve this limitation, we propose an intelligent SDP discovery scheme based on knowledge-based adaptive probing. It is composed of two main building blocks, SDP knowledge base and adaptive probing procedure. In the case study, a user device successfully discovers a new SDP version by means of the proposed scheme.