If you don't play online then:
1.Run the game and during loading check version's number.
2.Go to this URL
http://patches.ubi.com/il2_forgotten_battles/ and check if there is a newer version ( might be il2_fb_aep_v2.01.exe and il2_fb_aep_v2.04.exe )
3.Install new version if you have to.
4.A directory back is always good
