Download patch and hotfix.
Clear game cache folder
Code:
[Documents]\1C SoftClub\il-2 sturmovik cliffs of dover\cache
Use
winrar to extract the patch to your install folder which is typically
Code:
C:\Program Files (x86)\Steam\steamapps\common\il-2 sturmovik cliffs of dover\
Test the program runs and the correct version is displayed.
Install hotfix and test again.