Topbar transparency not changing??

Currently, I am making a custom topbar w/ contents inside it, and to achieve that, I need to make the default topbar transparent. But when I use the function SetTopbarTransparency(), it doesn't do anything. The topbar's transparency doesn't even change :p. Here is the code:

--< Variables
local customTopbar = script.Parent:WaitForChild("CustomTopbar")
local versionNumberGui = customTopbar:WaitForChild("VersionNumber")
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local RemotesFolder = ReplicatedStorage:WaitForChild("Remotes")
local GetServerVersion = RemotesFolder:WaitForChild("GetServerVersion")
local playerGui = game:GetService("Players").LocalPlayer:WaitForChild("PlayerGui")
local serverVersion = GetServerVersion:InvokeServer()

--< Events
playerGui:SetTopbarTransparency(1)	-- this doesn't even do anything
versionNumberGui.Text = 'patch 0.'..serverVersion

Even though you seem to have found your own solution, you could still make the topbar invisible using this:

game.StarterGui:SetCore('TopbarEnabled',false)