µMIDI 1.11 failing to firmware update

I’m failing to update my 1.11 µMIDI to the latest 1.15.
I am wondering if this is because mine is so old ?
Is there a way to get hold of previous firmware releases so I can try to install incrementally.

There’s no point in doing incremental updates. The bootloader is preprogrammmed into the CPU so t doesn’t change when you update the firmware. Each firmware is a total replacement.

What’s the specific problem you are having?