If the your DES-3226S switch is running a firmware which isolder than 4.01b23 then you will have to upgrade to thisversion.  You can then upgrade to the latest available versionof the firmware for the switch after this.

Once the firmware has been upgraded from R4.0 to R4.01, thefollowing features have to re-configured:

a. IGMP Snooping Global State
b. Multicast router Only
c. Link aggregation
d. Daylight Saving Time (Annual)
e. Syslog Server
f. Port Mirroring

You can download the v4.01b23 firmware from