Fuji is usually pretty good at providing firmware upgrades for their older cameras. It seems like the X100S is one of those rare exceptions—Fuji has publicly said they won’t be releasing major firmware updates since the X100T is on the market. That means that the Classic Chrome film simulation is only available in-camera on the X100T.
I say in-camera because if you’re using Adobe Lightroom there’s a workaround: change the EXIF info on your X100S .RAF RAW files to identify them as X100T files, and Lightroom will happily let you process them using Classic Chrome. This post on DPReview has links to the command-line program ExifTool, and examples. My recipe is usually this:
exiftool -model="X100T" -ext .RAF -r "/PATH/TO/MY/RAF/FILES/" -overwrite_original
and then after I process JPGs I flip the model back to X100S on the JPGs (since sites like Flickr bring up the camera model in the metadata).
exiftool -model="X100S" -ext .JPG -r "/PATH/TO/MY/JPG/FILES/" -overwrite_original
Be careful with those operations if you have a mixture of RAF and JPG files from different cameras. If you do, you might want to do these operations on a folder that contains just the X100S files.
Do I like Classic Chrome? For me it’s hit or miss. I think it looks really great in daylight. Indoors, I’d probably use a different film simulation or use a VSCO preset in VSCOCam.