How auto-update works
Obsidian checks for update every 12 hours. Once an update is available, restarting the app will automatically bring you to the latest version.
You can check your current version, check for updates in Settings => About. You can also turn off "automatic updates" there.
If you're looking to update to the latest insider build, please refer to this guide on how to turn it on.
Current version vs installed version
If you look closely in Settings => About, you can find your current version and your installer version.
Your current version is your Obsidian version. This is the version of the app on top of the engine (which is Electron). It will increase when you auto-update, but your installer version will not. Your installer version will only increase when you install Obsidian with a new installer.
Most features can be delivered by auto-updating, but to update the engine for certain new features Obsidian, we encourage you to grab the latest installer from our official website from time to time, when your current version is above the installer version by a lot, for example when your current version is 0.10.8 while installer version is 0.8.3.