Hi. Can you add item spawner support? I have iron spawner in my server for this reason i can not use SilkSpawners. I have a custom plugin but it is not good like SilkSpawners.

Yes. Iron ingots, diamonds and something like that. You can put every item in a mob spawner.

This offers: https://dev.bukkit.org/projects/item-spawner
But this is not even needed. You can take it with /setblock command.
/setblock ~ ~1 ~ minecraft:mob_spawner 0 replace {SpawnData:{id:"minecraft:item",Item:{id:iron_block,Count:1b}}}

More:
http://www.minecraftforum.net/forums/mapping-and-modding/maps/maps-discussion/2156116-q-how-to-make-custom-mob-spawner-that-drop-items
http://www.minecraftforum.net/forums/minecraft-discussion/redstone-discussion-and/2561310-1-9-solved-custom-spawner-spawn-potentials
https://mcstacker.bimbimma.com/

Okay, so basically it's just custom NBT data. It's already planned to let users define custom NBT data that is then copied to the item/block when obtained via /ss give or mined. This would also include custom item spawners like your example.

No ETA, but I hope to have more spare time in the next weeks.

You mean iron ingots as the "mob" of the spawner?