Instrument modifier and runspeed

[Pinedepain]

Hello everyone, I'd be glad if someone can help me with the following problem.

Client side speaking, even if a bard play a percussion song while holding a percussion instrument, there will be nothing that shows that the modifier has been applied.

For exemple, I run at the same speed with or without a drum while I'm singing Selo's.

I've searched in the server sources and I haven't found anything that could let the client know that he has a modifier.

My question is : Is it handled client side or do I need to send something to the client to set the correct runspeed for exemple? If yes, what should I send? If no, is my client broken?

I thank by advance everyone who'll try to help me!