Today, the Invasion event officially ended. With this, the official Valve servers for the event also shut down, removing all chance of playing the officialized Invasion maps on official Valve servers. When the Gun Mettle campaign ended, the maps that were added to the game were added to the standard Valve rotation on Valve servers. In other words, the servers would randomly roll on to them, and can be voted for them to be set as the next map. However, for Invasion maps, none of the maps are available to vote as the next map on Valve servers currently. Gun Mettle maps are still there, however. There's roughly 20-ish servers currently running arena_byre, pd_watergate and koth_probed, and another 20 running ctf_2fort_invasion. As it stands, those servers are the only way to play Invasion maps currently. While understandably arena_byre is a bit of an oddball to fit on to any of the current server rotations, what with there being no Arena servers, koth_probed can easily fit in the KOTH rotation, and pd_watergate could either go in KOTH or CTF/SD. ctf_2fort_invasion could also fit in the CTF section, but might be best left to throw in to the Halloween rotation next year. I hope Valve considers adding some of those maps to the main rotation. Otherwise they're doomed to die a wet, hydroelectric death.