Reply To: How to disable and or modify the "Sold Out" label.

Hello,

Please add this code to the Theme Settings > Custom CSS > Global:

/*sales*/ body .labels-rectangular .onsale { 
color:#ffffff; 
background-color:#000000; 
font-size:12px; 
}

Edit as per your needs, you can change the color, background color, and reduce the size.

Best Regards