Trouble using suplabel() to create global axes for figure with multiple subplots

Hello, I am having some trouble using suplabel(). I want 2 global axes labels (one x and one y) for my figure that contains multiple subplots. I was able to do this with the title using suptitle() so I am assuming I have a version of Matlab that can handle suplabel() as well but I am not getting it to work. Does anyone know why this might not be working? I get the following error message:

>> PostProcessing_filetest

Undefined function or variable 'suplabel'.

Error in PostProcessing_filetest (line 266)

suplabel('Frequecy(Hz)','x')

I have attached a portion of my code if that helps. Thanks!

 %Create Plots

 for j = index 

    figure(fignum)
    fignum = fignum + 1;
    hold on
    for i = 1:numfiles 
        subplot(numfiles,1,i)
        y = Farray(2:end);
        yt = transpose(y);
        x(:,:,i,j) = NewAmp(:,:,i,j);
        xt(:,:,i,j) = transpose(x(:,:,i,j));
        plot(y,xt(:,:,i,j))
        title(fn(i))
        axis([0 Fmax 0 1.5*maxNewAmp(:,:,i,j)])  
    end
    t1 = strcat("Reference Probe: ",fn(j));
    t2 = strcat(namexparm, " = ", string(xparmmax(:,:,j)),"(", unitsxparm, ")");
    suptitle({char(t1);char(t2)})
    suplabel('Frequecy(Hz)','x')
    suplabel('Amplitude', 'y') 
    hold off
end

Answer 1

[Sindar]

sublabel does not exist in Matlab releases. You can download the user-created sublabel from the File Exchange and put it on your matlab path