For what it is worth, this comes up regularly:
You can see many opinions on there. He did go back in 2020 and updated part of the course, but the main material is quite old.
I am not sure if or when Mosh would consider updating the whole course (ie.creating a whole new one rather than just adding some update videos to the old one). I am sure it is extremely time consuming which is why he has not done that already.
@Mosh (in case Mosh is willing to address this topic directly)
The gist I get is that React has changed considerably in the past several years and just patching the course is insufficient at this point. Those using the course are generally disappointed at how outdated it is.