smtpd_command_filter

[Hari Hendaryanto]

hi,

i'm using postfix 2.5
i've been flooded with "Illegal address syntax from" from my customers 
which are using crap email client.

Log shows:

Dec 21 15:48:40 lb1 postfix/smtpd[68202]: warning: Illegal address 
syntax from 202-127-103-114.triplegate.net.id[202.127.103.114]:3608] in 
RCPT command: <'someu...@yahoo.com'>

How can i adopt "smtpd_command_filter" with postfix 2.5? is there any 
workaround to rewrite rcpt to: on the fly?

upgrading postfix would be the latest choice.

thanks