The butane and butene fluids have identical icons, which show a ball-and-stick model for butene ( C4H8 ). This caused me a bit of confusion after first setting up refinery gas processing. I propose that the icon for butane should have the ball-and-stick model of C4H10 (https://commons.wikimedia.org/wiki/File:Butan_Lewis.svg#/media/File:Butan_Lewis.svg)

this actually has been changed for 0.6.500! they have new icons (as well with essenitally all PM ores), i am just about to upload a patch and i'll include the new butane/butene icons in it :]
they are still similar, but are more differenitated then the current icons - hopefully this should help

Thanks!

no problem!

Is there a release window on 0.6.500 or will it just happen?

not really? not right now at least, its still pretty early in development (i’ve had to spend a lot more time on updating the public version then the new major update) - i expect it to be done within the next couple months though :]

(of course feel free to look on the discord server for any active development, if you are interested)