To update other versions (8-9-10-11) to version 12 - it is not possible! It is necessary to Contact the company-manufacturer - Graphisoft, there there are special offers about it. And to update AC12 to new build - it is possible in the same place, having downloaded so-called "Patches":
AC12-2285hotfix #1
AC12-2325hotfix #2
AC12-2420hotfix #3
AC12-2523hotfix #4
AC12-2675_hotfix #5 - last for today build