Stand alone panel

Hello! I’m working in school and we adding classrooms, ecxisting school has Bosch panel but addition classrooms silent knight question is by code is it required for both systems to be connected together?

ALWAYS reference the applicable NFPA publications AND adhere to ALL local codes and regulations when working with life safety equipment. That virtually always means a LICENSED contractor must do any and all fire system work. If you are not authorized you should not make any system modifications.
If the expansion is not 2 separate buildings, then yes absolutely the fire system(s) must all be interconnected. If the existing Bosch system is conventional, I’d highly recommend just replacing the Bosch panel with the Silent Knight panel and running all the wires to the one location, that way there’s just one panel managing the whole system and you don’t need to worry about relays and configuring inputs just to make the panels trip each other. In fact, 2 separate panels is going to be a headache for the installer, the user, and the fire department.
If the expansion involves separate buildings, the panels probably don’t have to be linked unless the buildings are very close together. Again, ALWAYS refer to local ordinances and regulations before beginning any work.

Thank you for your help