The invasion server is back with a slightly different approach. Here is the rotation.
Walls of Bariyye
Walls of Suno
Middle of Nowhere
Walls of Uxkhal
Most of them were made by Taleworlds, Earnside Castle was made by gokiller, Middle of Nowhere was made by Aeneu, Mynyw Fort was made by Adorno and Kalran Castle was made by DXaero and Ettenrocal. I edited them to be fully playable in the invasion mode. Enjoy!