It is very simple, just compare both functions: esp_err_t esp_ble_mesh_server_model_send_msg(esp_ble_mesh_model_t *model, esp_ble_mesh_msg_ctx_t *ctx, uint32_t opcode, uint16_t length, uint8_t *data) { if (model == NULL || ctx == NULL || ctx->net_idx == ESP_BLE_MESH_KEY_UNUSED || ctx->app_idx == ESP...