isthmus easy to ? upgrade office 11 for 4 bit?

I'm afraid there's no way.

Microsoft only supports upgrading MS Office 2016 32-bit up to 64-bit with a special updater they released.

However, for anything older like MS Office 2011 they no longer support those old versions. If you contact them they will tell you to buy MS Office 2019 or an MS Office 365 subscription.

Look into the Free LibreOffice, it handles MS Office files…

https://www.libreoffice.org/