MODE <nick> +s <+|-><modes>

Server notice masks:

    SNOMASK     DESCRIPTION
-----------------------------------------------------------------
       +b     - Possible spambot/flooder warnings
       +c     - Local client connections and exits
       +C     - Extended local client connections and exits
       +d     - Server debug messages
       +f     - Clients refused due to limits
       +k     - Server and service kill messages
       +n     - Local client nick changes
       +r     - Invalid usernames and dumb HTTP proxies
       +s     - Generic server messages and oper kills
       +u     - Client connections without auth{} block
       +x     - New server introduction and split messages
       +y     - Juped channel join attempts, etc
       +Z     - Operspy usage