After upgrade, the custom icons are missing on the instance, getting "Failed to decode downloaded font: " error on the browser console.Issue <!-- div.margin { padding: 10px 40px 40px 30px; } table.tocTable { border: 1px solid; border-color: #e0e0e0; background-color: #fff; } .title { color: #d1232b; font-weight: normal; font-size: 28px; } h1 { color: #d1232b; font-weight: normal; font-size: 21px; margin-bottom: 5px; border-bottom-width: 2px; border-bottom-style: solid; border-bottom-color: #cccccc; } h2 { color: #646464; font-weight: bold; font-size: 18px; } h3 { color: #000000; font-weight: bold; font-size: 16px; } h4 { color: #666666; font-weight: bold; font-size: 15px; } h5 { color: #000000; font-weight: bold; font-size: 13px; } h6 { color: #000000; font-weight: bold; font-size:14px; } ul, ol { margin-left: 0; list-style-position: outside; } --> Symptoms After upgrade or clone, the custom icon or fonts are missing on the instance and in the browser console, you will be getting the below error message as "Failed to decode downloaded font: <URL>" For Example: Failed to decode downloaded font: https://<instance-name>.service-now.com/sys_attachment.do?<sys_id>assurance?id=customer_search:1 OTS parsing error: invalid version tagassurance?id=customer_search:1 Failed to decode downloaded font: https://<instance-name>.service-now.com/sys_attachment.do?<sys_id>assurance?id=customer_search:1 Failed to decode downloaded font: https://<instance-name>.service-now.com/sys_attachment.do?<sys_id>assurance?id=customer_search:1 OTS parsing error: invalid version tag Release Any Cause In the CSS includes, the font or the icon are included as an attachment, which is missing. Resolution Import the font or the icon attachments from the working instance to the respective file on the CSS include. Additional Information Custom Fonts in Service Portal