Version 4.0 was released on December 18, 2008. Symantec also markets a bundle of Version 4.0 and the 2009 version for Windows, intended for users with both Microsoft Windows and Mac OS X installed. iClean was dropped from this release. The firewall now blocks access to malicious sites using a blacklist updated by Symantec. To prevent attackers from leveraging insecurities in the Mac or installed software, exploit protection was introduced in this release. Phishing protection was introduced in this release as well. Operating system requirements call for Mac OS X 10.4.11 or higher. Either a PowerPC or Intel Core processor, 256 MB of RAM and 150 MB of free space are required.