Yeah, it's not unusual for modules to change from year to year. Core modules tend to change less frequently than optional modules, but they do still change sometimes.
As for changing courses - Some unis are more flexible than others about changing courses part way through. In general, they're more likely to allow you to switch if the first year of both courses is the same or very similar. If you're sure you want to change, speak to them before you start or as soon as you arrive and see if you can change before starting.