Judging by screenshots,the following version of Russian flag is used in the game http://en.wikipedia.org/wiki/Image:Russian_Empire_1914_17.svg
However it looks pretty strange with that yellow corner. The wikipedia reads:
"A variant of the flag was authorized for private use by Tsar Nicholas II during World War I, adding the Romanov eagle on a yellow field in a canton in the top left-hand corner. This variant was never made official."
(http://en.wikipedia.org/wiki/Russian_flag)
So why using it in the game since it was not official???
And honestly with that yellow patch it looks somewhat ugly. How about shifting to official version with the next update?