Can't load my save because of this mod, needs an update.

Same here.

Copy of the error text

Some mods failed to load. Update or remove the affected mods and try again.

System.MissingMethodException: Method not found: System.Collections.Generic.IReadOnlyDictionary`2<Mafi.Tile2iSlim, Mafi.Core.Roads.GraphTerrainConnection> Mafi.Core.Roads.RoadsManager.get_TerrainGraphConnections()
  at (wrapper managed-to-native) System.Object.__icall_wrapper_mono_gc_wbarrier_generic_nostore_internal(intptr)
  at (wrapper write-barrier) System.Object.wbarrier_conc(intptr)
  at (wrapper managed-to-native) System.Reflection.RuntimeConstructorInfo.InternalInvoke(System.Reflection.RuntimeConstructorInfo,object,object[],System.Exception&)
  at System.Reflection.RuntimeConstructorInfo.InternalInvoke (System.Object obj, System.Object[] parameters, System.Boolean wrapExceptions) [0x00005]  

Game version: 0.8.6
Loaded mods: (Trains expansion 1.0.0), (Kayser's Automatic Terrain Designations 0.5.2), (BeTTerLife: Roads and Signs 1.0.10), (BeTTerLife: Retaining Walls 1.2.2), (Place Virtual Resource 0.4.4), (Research Queue 1.0.1), (Retaining Walls Never Die 1.0.0)
Failed mods: none

Same Issue I'm having

Some mods failed to load. Update or remove the affected mods and try again.

System.MissingMethodException: Method not found: System.Collections.Generic.IReadOnlyDictionary`2<Mafi.Tile2iSlim, Mafi.Core.Roads.GraphTerrainConnection> Mafi.Core.Roads.RoadsManager.get_TerrainGraphConnections()
at (wrapper managed-to-native) System.Object.__icall_wrapper_mono_gc_wbarrier_generic_nostore_internal(intptr)
at (wrapper write-barrier) System.Object.wbarrier_conc(intptr)
at (wrapper managed-to-native) System.Reflection.RuntimeConstructorInfo.InternalInvoke(System.Reflection.RuntimeConstructorInfo,object,object[],System.Exception&)
at System.Reflection.RuntimeConstructorInfo.InternalInvoke (System.Object obj, System.Object[] parameters, System.Boolean wrapExceptions) [0x00005]

Game version: 0.8.6
Loaded mods: (Trains expansion 1.0.0), (Supporter edition 1.1.0), (Kayser's Automatic Forestry Designations 0.1.11), (Kayser's Automatic Terrain Designations 0.5.2), (BeTTerLife: Roads and Signs 1.0.10), (BeTTerLife: Transports 0.6.0), (Ore Sorters Storage Boost 0.1.0), (Pillar Spacing and Height Mod 1.0.1), (Research Queue 1.0.1), (ShipAutoExplore 0.1.0), (Underground Transport 5.2.0), (Wind turbines 0.1.11a), (Cheat++ 1.2.7), (Gameplay++ 1.2.7), (Recipes++ 1.1.7), (Speed++ 1.0.5), (Tweaks++ 1.2.0), (Utilities++ 1.1.5)

The version that was just pushed a few minutes ago seems to be working correctly! Updated via in-game mod browser.