New
#321
Just download the ISO when it's available via Media Creation Tool. https://www.microsoft.com/software-download/windows10
17134.5 is the latest stable build, the release build will likely be 17134.1 with an immediate WU to complete, I would just stay on the Release Preview build It will not make any difference until the 1809 release.
You should be able to exit the program once the release is official, of course you may find that coming out of the program will delay any future builds if you re-join later
I'm not sure if one can leave IP without complete reinstall, at least it was like that before.
The Release Preview works through Windows Update anyway, the only difference is that everything is slightly speeded up - Eg. If microsoft decides to release an update on a particular Friday, the Release Preview get it a few days earlier, in this imaginary case likely the monday previously.
There is not the issue that there is in the Fast and Slow rings, ( where you are running a beta OS so need to replace this to leave), as you always run an official public release so should be able to leave anytime the official release matches yours which is anytime except the few days between the early release and the official release.
Technically this should also be possible if on the Fast or slow Ring and the current version turns out to be the RTM - but there is also the case of any potential debugging code that is present in the Fast/Slow ring build, so Microsoft insist on the Fresh install, for build stability reasons