Ever since 1.11 came out I have not been able to summon horses. I have always used the same code and it used to work fine in 1.10. Here is the code I used: /summon EntityHorse ~0 ~1 ~0 {Attributes:[{Name:generic.maxHealth,Base:60.000},{Name:generic.movementSpeed,Base:0.3375},{Name:horse.jumpStrength,Base:1.0}],Type:0,Tame:1,SaddleItem:{id:329}}
Entity IDs have changed in 1.11, and the horse entity has been split up into
minecraft:horse,minecraft:donkey,minecraft:mule,minecraft:skeleton_horse, andminecraft:zombie_horse. TheTypetag has been removed as well due to this.