One of the trickest parts of web development is ensuring your code is backwards compatible, there are a variety of utilities that can be utilised in order to assist with this, below I’ve listed the most useful ones that I have found.
Internet Explorer Application Compatibility VPC ImageThe most useful of these utilities is provided by Microsoft, realising that a lot of people were still using older versions of Internet Explorer they release Virtual PC (external link) images containing versions of Internet Explorer from version 6 onwards. The images expire after a few months but Microsoft are constantly updating them to include the latest Windows updates. Download the Internet Explorer Application Compatibility VPC Images (external link) from Microsoft’s site. |
 Browsershots (external link) is a open source web farm running multiple versions of operating system and browsers which can be used to check rendering of a single web page. As it is free it can sometimes fail to render your page on certain selections and can also take a long time to render but it is very helpful to see what it will look like on more obscure operating system and browser combinations. |
 Litmus (external link) is a website that offers paid for and free versions to show you how your web pages and emails render in various browsers and/or email readers. It is more reliable than Browsershots but the free version’s list of browsers is limited. |