This support statement is provided by the Product Management Team. 

We announce the End of Sale for Network Security NS-3500 Appliances. The End of Sale date is October 11, 2021.
As of this date, these appliances will no longer be available for purchase. 

The NS-3500 appliance will reach End of Life and End of Support on September 30, 2026. Existing customers will receive support until that date, in accordance with the Enterprise Products End of Life Policy.

The NS-3200 applicance remains available as the low-end option for customers.