Hi,
Currently latest is 0.3.2.3.1, 0.3.3 is still paid build only.
If you're asking on how to update TO 0.3.2.3.1 from some build lower like 0.3.2 or 0.3.0.1 etc. then simply download latest build from here and install it (the pop up prompt will ask you if you want to "update" the app instead - yes you want that.
If you uninstall previous build to install new one, your save data will be gone as well.
Cheers