New
#250
RTM = Released to Manufacturing (or Ready to Manufacture, as I like to call it)
IS a very relevant term which enables us to identify the build which is feature complete and has no time expiry:
It is the base build (eg 15063.0 etc...) from where computer system manufacturers can start testing and building their specific configuration for their hardware. This is also the stage where we will start to see new patches but not new builds, that only fixes Windows internal bugs and security flaws.
All this has nothing to do with GA = General Availability, which is just a term when everybody has access to latest Windows version. This will happen much later than RTM. GA build is exactly the same as the RTM build, but it has already received a lot of patches. A new version of Windows will be released to the general public once it's declared stable enough for majority of users, including the non tech savvy ones. RTM is NOT stable enough for all users.