Back in January, Microsoft launched modern.IE to help developers ensure that their sites work well with different versions of Internet Explorer. The modern.IE site came with a variety of tools and resources, with a particular focus on helping non-Windows developers deal with the real challenge of users on older versions of IE. So taking this development to the next level, Microsoft added to its compatibility-testing offerings with Windows QuickStart Kit for Mac developers, priced at $25. This includes a new code scanning tool for sites behind a firewall and virtual machines for IE 10 on Windows 7 and IE8 on Windows XP.

The USP of this release is that developers can get their hands on the kit—which includes Parallels Desktop 8 (normally around $75) and Windows 8 Pro (up to around $120)—on a USB stick in exchange for a $25 donation to charity.

“We heard that the most common way you test across browsers is through virtualization of browser and operating system combinations using your favorite virtualization platform, such as Hyper-V, VMWare, VirtualBox, or Parallels. However, costs to purchase software and licensing can be difficult if you’re that startup looking for your first big breakthrough. Today we’re making it just a little easier with a new combo offer,” Microsoft said introducing the kit on Tuesday.

The kit is available through online retailer Swish, but has sold out completely.

Once it becomes available again, developers can pre-order theirs here on Swish.com. To ensure that only developer can order the sticks, Microsoft added a small puzzle on the check-out page. The sticks are scheduled to ship by the end of April.

With enhanced capabilities, modern. IE allows developers to quickly scan websites and resolve any compatibility issues. With the new tool, Microsoft allows developers to scan sites that sit behind firewalls by installing a local instance of modern.IE through node.js. In addition, Microsoft now provides developers with more ideas for how to fix issues using Compat Inspector tool powered by Sauce Labs, and utilize breakpoint detection for responsively designed sites and touch-optimization detection.

With this release, modern.IE is now also available in 18 languages including Arabic, Bahasa Indonesia, Chinese (Simplified, Traditional, and Hong Kong), Dutch, French, German, Italian, Japanese, Korean, Portuguese (Brazilian), Russian, Spanish (Spain and Latin America), Swedish, Thai, Turkish, and Vietnamese.