Older avast versions available?

I bought a used Macbook 4.1 with Snow Leopard OS X, which is the latest version that will work on this Mac.

I tried to install the current avast version for Mac, but it comes back and says that it won’t work with my current OS version.

Is there a place where I can download an older version that will work with Snow Leopard?

Avast works on Snow Leopard, if it is 64b. If you can not install Avast, then your Mac is 32b and there is no version of Avast that it would make sense to run on it as we do not provide 32b VPS (virus definitions) anymore.