Hi, I'm new here. This might be a bit obvious but can the two power rails in the user section of the caravel harness be set to any voltage for example 5v instead of 3.3v. Thanks in advance.

there are 4 separate rails for the user project. And they all have pins on the physical package so you c an connect them to what you want. 5v is the maximum.

Not quite. The VCCD domains (VCCD1, VCCD2) have to be set to 1.8V, as they are connected to low-voltage clamps and other low-voltage logic. The VDDA domains (VDDA1, VDDA2) can be set to anything from 1.8V to 5.5V.

Great! Thank you both for the help.