A couple of months ago we were able to see how Apple was starting to name the operating system of Mac computers as macOS in a framework on OS X 10.11.4. Shortly after, on a company website for the environment, he also referred to the Mac operating system as macOS. As if that were not enough, yesterday on the iTunes Connect support page there was also another reference to Mac OS X as macOS, another new allusion to the possible name change of the Mac operating system. A few hours after the publication of this news, Apple has modified the entry and in its place we can now read Mac OS X instead of macOS, as we can see in the image that heads this article.
We currently do not know if the change will take place or not, but so far We have already seen three different references where macOS is used instead of Mac OS X. Currently the iPhone / iPad / iPod Touch, Apple TV and Apple Watch operating systems use lowercase letters at the beginning of the operating system name: iOS, tvOS and watchOS represent common names not registered by the company while the operating system of the Mac OS X refers to the computers manufactured by the company, hence the first letter is written separately and in capital letters.
However, it makes sense that Apple wants to change the name of Mac OS X to MacOS in order to match the name of all operating systems designed by the company and found on your devices. The modification by accident or intentionally could be a clue to the company's intention to announce the name change at the next WWDC to be held next week in San Francisco.