I tried taking my biome from 1.6 to 1.7, but got some errors with it. Here are the lines with errors:
CakeyMod.java:
public static BiomeGenBase ShroomBiome(58).setBiomeName("ShroomBiome").setMinMaxHeight(0.2F, 1F);
GameRegistry.addBiome(ShroomBiome);
ShroomBiome.java:
topBlock = (byte)CakeyMod.ShroomGrass.blockID;
fillerBlock = (byte)CakeyMod.ShroomGrass.blockID;
(I have got the ShroomGrass block working, so it can't be causing the errors in ShroomBiome.java.