Samsung is seeding the Galaxy Watch4 with a new firmware update. It brings camera zoom controls, new device diagnostic tools, and other stability fixes. The update is R860XXU1GWA3 It’s a build number and is just under 330MB in size.
Galaxy Watch4 R860XXU1GWA3 update changelog
A big new feature is the zoom toggle within the watch’s camera controller app. This feature only works on supported flagship Samsung smartphones from Galaxy S20 and Galaxy Z Flip onwards. To control the zoom level, his two options are using the rotating bezel and pinch-to-zoom on the smartwatch’s touchscreen.

Another new feature with the update is the device diagnostic tool. This tool allows you to check your watch’s battery status and touchscreen capabilities via a connected phone.
sauce (reddit)