We saw Apple's first demo of the new Mac operating system at WWDC in June 2019.
The new operating system will be available to download in the autumn - so probably September as usual, but it could be October.
However, you may not have to wait as long as that. If you are a
registered developer you can download the beta of Catalina now, and if
you sign up for the public beta you can get your hands on the Catalina
beta in July.
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