1.6.4
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  [+] core UI improvements, "you are offline" and "new features" notification panels
  [+] online/away operators list (on "awaiting visitors" page) by Andrew Armstrong
  [+] several instances of mibew in one DB ($mysqlprefix variable)
  [+] ability to override notification email for group
  [!] various compatibility fixes: button image, captcha, check webimroot variable (installation)
  [!] check file permissions/checksum (installation)
  [!] fix speed of history search, fix redirection to groups
  [!] fix sound issues in windows