The program of upgrade of the Spherical Neutral Detector for future experiments at a new VEPP-2000 $e^+e^-$ collider is presented. Modernization includes upgrades of electromagnetic calorimeter, tracking system, detector electronics, data acquisition system, and offline software. It is also planned to equip the detector with two new subsystems: particle identification system based on aerogel Cherenkov counters and external electron tagging system for $γγ$ physics.
