Will older models never get newer film simulations with firmware updates?

It’s a safe bet these days that the only film sims you get are those that are in the camera when you buy it.

Despite it often being a widespread expectation when new film sims appear, Fuji have literally only ever updated older cameras with a new film sim once - some years ago, when they introduced the very first “new” sim Classic Chrome. That was released on one of the X-Trans II cameras (I forget which) and a number of others then received it via firmware, but only those X-Trans II models - the first gen X-Pro1 and XE1 never saw it for example.

The next new sim was Acros, announced with the X-Pro2 which also happened to be the first X-Trans III camera, and at that time Fuji specifically explained how the special grain processing in that sim couldn’t be replicated on older hardware so it would never come to older models.

That reasoning kind of made sense at the time, but doesn’t hold for the number of sims since that haven’t been shared by firmware either. For example Eterna was the next new sim announced with the XH1, an X-Trans III camera with the same image processing as the X-Pro2, XT2, XE3 etc, but none of those older cameras got it. Similarly Classic Neg was released on the X-Pro3 but never shared with the internally identical XT3, and now it’s the same with Eterna Bleach Bypass on the XT4. At this point the pattern is pretty well established, to get the new sim you need a new camera.