Did you open the App Store (press the top left apple-icon - App Store...), and select upper right "Updates".
You should have macOS Sierra Update (10.12.5).
Press the Update button to install it.
If update this does not appear, search in the App Store for: macOS Sierra.
Download and install.
that's weird, the update doesn't show when i do a software update but i have to search for it???
is this really out of beta?
Have you ever open mac app store? Have you ever searched for the xcode or xcode ide in the mac app store? You should go for the XCode in app store for the developing anything like apps of game, apps of education etc. So my advice is that you should go for the xcode and start developing through it .