So the answer is yes. There is a 5.4.0 version and you can find it on the Hikvision Europe firmware portal. I upgraded a DS-2CD2332-I earlier in the week, had a poke around and then downgraded again. Be aware if you upgrade to this version you won't be able to downgrade unless you either crack it open and get to know the serial terminal, or use a modified firmware posted earlier in the week by Enabler that should allow you to downgrade.
Unless you have a specific use case for any of the minor fixes in the firmware I'd stay clear of it. It does not bring anything worth upgrading for. To be honest it has been my experience that it's not worth upgrading Hikvision firmware *ever* unless you are trying to fix a specific issue you know is fixed in a later version. All they seem to do is remove features that were perhaps over-optimistically put in at the start, and introduce new and annoying bugs. Let's say I don't hold their firmware QA/QC in high regard and their release notes are a joke.