ClientMessage doesn't seem works on 4.15.3

According to:
A new, community-hosted Unreal Engine Wiki - Announcements and Releases - Unreal Engine ForumsObject%26_Actor_Iterators,_Optional_Class_Scope_For_Faster_Search

for ( TObjectIterator<USkeletalMeshComponent> Itr; Itr; ++Itr )
	// Access the subclass instance with the * or -> operators.
	USkeletalMeshCompoment *Component = *Itr;

ClientMessage(“My text”) doesn’t seem to works at all. I tried to include any of those:

#include "EngineUtils.h"
#include "Runtime/Engine/Classes/GameFramework/PlayerController.h"
#include "GameFramework/PlayerController.h"

Yet, I still get:
‘ClientMessage’: identifier not found

Also, ENGINE_ClientMessage doesn’t seem to works either

Weird, anyway I don’t strongly recommend you doing that. What I would recommend, is to define a set of integer’s defining a set of pre-defined messages, e.g.:

const int MESSAGE_ID_WELCOME = 0; // " Welcome to our Game"
const int MESSAGE_ID_PLAYER_DIED = 1; // "Player %playername% died"

You’d send:

SendMessageId(1, instigator->GetName());

Something like that. Obviously you’d need to have the strings mapped to the corresponding ID in the client-side. Sending plain texto is a waste of precious network resources x)