43.943 Applying migration: Robot Army: robotarmy_0.1.3.lua
43.998 Applying migration: Robot Army: robotarmy_0.1.4.lua
44.049 Applying migration: Robot Army: robotarmy_0.1.41.lua
44.099 Applying migration: Robot Army: robotarmy_0.1.42.lua
44.150 Applying migration: Robot Army: robotarmy_0.1.43.lua
44.204 Applying migration: Robot Army: robotarmy_0.1.44.lua
44.258 Applying migration: Robot Army: robotarmy_0.2.0.lua
44.311 Applying migration: Robot Army: robotarmy_0.2.1.lua
44.354 Warning Scenario.cpp:220: Map loading failed during migrations processing: Error while applying migration: Robot Army: robotarmy_0.2.1.lua

robotarmy/migrations/robotarmy_0.2.1.lua:21: attempt to index field 'rally-beacon' (a nil value)
44.430 Error ServerMultiplayerManager.cpp:95: MultiplayerManager failed: "Error while applying migration: Robot Army: robotarmy_0.2.1.lua

I commented out each mention of the beacon in the migration files and it works. There appears to be a message about not using them when loading into a game.

And now I see a thread addressing this issue derp. All is well.