If your software is really old you may have an app called "Market Updater". If so, disabling/freezing or removing that should stop the updates (this doesn't work on newer devices, where that app no longer exists).
However, if your software is that old you probably won't have the option to disable it, and you won't be able to remove or freeze it unless you are rooted. So in that case I don't know whether there is anything else you can do.