By William L. Kiely, Reuters—Microsoft on Thursday said it is in talks with several security firms about launching a new version of its antivirus software called Microsoft Windows Defender.

The new software will be free for Windows 7 and Windows 8 users, but it will be available for $49.99 for Windows 8.1 and Windows 10 users, according to a release from Microsoft.

Microsoft has not specified how many users will get the software.

Windows Defender is designed to be the “default” antivirus suite for Windows users, so it will not be included in the Windows 10 Anniversary Update.

Microsoft is also planning to include Windows Defender in the new Windows 10 Creators Update, which will include features such as Microsoft Edge and the new Cortana personal assistant.

Windows 10 Creator Update is scheduled to be released in April.