Before folks start screaming, “You don’t care about us!”, please realize it is only because we care that we are developing Firestorm for you, and it is because we care that we are enforcing blocks. It is important for everyone to be on current releases that support the virtual world platform, its features and its capabilities.
Firstly, we are under pressure by Linden Lab to do this, and we can either do it ourselves or adopt LL’s update system which allows them to do it instead. Either we update you or LL does, but either way updating is quite inevitable. The LL viewer enforces updates, as do most all software applications with a fair grace period. Our grace period will be two versions behind the current release.
Secondly, updating is necessary in order to keep everyone enjoying the same shared experience. Second Life is not immersive if we see things drastically differently from one another. This is going to sound harsh, but in some respects if you are using versions that can only render avatars gray and/or versions without mesh, you might as well be—and perhaps should be—using a text based viewer.
Thirdly, it is hard for us to support. Even though we don’t officially support these old versions, it does not stop people from asking for support, to which we then have to respond by nagging them to update.
We recognize there are some users who cannot update to a current version due to their computer systems not being modern enough. For you there are still a few options. In some cases, people who believe they cannot run later versions of Firestorm are actually experiencing a fixable issue with which support can help; see the troubleshooting guide on our wiki. Contrary to popular belief, it only takes a computer around a US$300 value or so to run Firestorm. Firestorm does not require a “gamers” computer. Just something from the last five to six years will usually do. A decent video card will go a long way and often is all that is needed to dramatically improve performance for you.
You can download the latest version from here, there's even a link to currently available older versions. http://www.firestormviewer.org/downloads/
Adapted from this blog post.