In general (I have to update a correction on an earlier post here...), DOT 2, 3, 4, 5.5 are interchangeable, period.
DOT 5 is silicon based, while it "may work" it does NOT absorb water (part of my correction earlier), thus, any water in the hydraulic fluid settles to the low spot (part of that specific density bit.....now you know why you needed to pay attention to chemistry and physics in school.......
"Fluid compressibility" remains the same, just what it does with water since NO brake system it totally closed. They all have brake vents for the reservoir. Thus, they ALL allow some tiny bit of water in......