Is it mandatory to use heatsink and thermal interface with SSR P range of SSR (Solid State Relays).

SSR P (Panel mounting type SSR) does not with inbuilt heatsink compared to the integrated heat-sink
of SSR D (Din rail mounting type SSR) relays.

It is mandatory to use heatsink and thermal interface accessories for better thermal conductivity in between
SSR and the environment in which it is mounted as it is designed with a maximum operational temperature of 80 degrees C.