Subnautica's a fantastic game, and it launched in a pretty capable state. However -- as always -- there were some bugs to be squashed, and Unknown Worlds Entertainment has been hard at work "prototyping potential Subnautica expansions, working on Xbox One launch, and working on tidying up some of the more glaring bugs in the Steam 1.0 release".
Today, the last part of that sentence comes true, with the release of Update 84 -- the first unnamed Subnautica patch since Update 8 or so, like two years ago. Here's what it fixes:
The team started using proper patch names like the "Seamoth Update, because they were punchier, but apparently had nothing to name this one and went with the number route. Internally, updates always had numbers attached instead of titles.