For the release of the first expansion pack, The Burning Crusade, the a majority of the logo was changed to a green hue to represent the expansion.
For the release of the second expansion pack, Wrath of the Lich King, the logo was changed to a lighter blue hue with some snow and ice effect adorning the frame.
For the release of the third expansion pack, Cataclysm, the logo was changed to a red hue, with the globe modified to resemble a "Scorched Earth" style. The frame also received some damage and some fire effects were added to the background.
For the release of the fourth expansion pack, Mists of Pandaria, the logo was changed to a Sea-Green hue, with some serpents adorning the sides of the frame.
The logo for the fifth expansion pack, Warlords of Draenor was revealed on November 8th, 2013. The logo adopts a wood-paneling background with brackets along the sides of the frame. The globe has been darkened to a smoke/black colour mix and the frame has also received some minor damage and cracking. Also, the globe has a map of Draenor instead of Azeroth.
The logo for the sixth expansion pack, Legion.