Can't upgrade buildings – Farm Frenzy: Viking Heroes (Free) Review

Can't upgrade buildings on most of the levels. If you are able to upgrade, it only goes up once even though I have maxed out on buying all of the levels in the store. I like this series but don't know what's wrong with this version. I suggest coming back when they work out the bugs.
Review by What's wrong????!?! on Farm Frenzy: Viking Heroes (Free).