Forum:How can i make my general past level 4??

i just resumed playing castle age and was out for about a year. I noticed that the MAX level for generals has gone up from level 4. Can anyone tell me how to get past level 4? i tried to use the generals again to gain level but i does not change. Like Celesta, based on this webpage, it shows that she can reach level 10. How can i do that? please advise

Sonix