Originally Posted by UEFA
Unless stipulated otherwise in these regulations, matches in the competition must be played in a stadium which meets the structural criteria of the following categories as defined in the UEFA Stadium Infrastructure Regulations (2010 edition):
a) category 2 for the first and second qualifying rounds;
b) category 3 for the third qualifying round and play-offs;
c) category 4 from the group stage to the semi-finals;
The final must be played in a stadium which meets the structural criteria as defined in the staging agreement.