We don't have a non insider version of wp10 yet. It's frustrating. To hear Redstone 2 has been pushed back makes me weep for an official wp10 build.
Stay where you are........242 is a later release, it is .218 with bug fixes. .242 has been more stable than .218 on my two 640s and my 950.....what you get on Insider release is 100% the same as "official".....insider PREVIEW ring is the last step before release....just stay put unless you have issues.