We’ve had a discussion about this in the matrix chat.
They said they plan on allowing customization, like color schemes. However they do not plan having themes in the sense of having a way to have the app look completely different, for example a windows 95 theme.
So from my understanding it will be similar to what Apollo had.
I would like to be able to change the interface colour. Lemmy allowed me to enter a hex code and change all the default blue elements to a colour of my choice — I love that.
Apollo alas never offered that, but at least it had some predefined options that were kind of close to my choice.
I can submit this as a formal request later today.