If it says that it's not up to date, you probably downloaded an outdated APK. To download the latest version, visit vegax.gg and download for Android. Ensure not to use any Linkvertise bypassers because those will give you outdated links.
If you are positive that you are using the most up-to-date version, try restarting the emulator. If that doesn't work, the version is probably outdated, and you may need to wait for an update.