SyncNow checks once when it starts and, while Automatic checks is ticked, about every minute while it is open (less often after errors); when it finds a new version it may also ask you once, with Update now or Later.
Click Updates to see the new version: the title names it, for example SyncNow 13.2.49.61 is available, the page lists its notes under What's new in this update and has the Update to v… button; installing restarts SyncNow when it finishes. If you choose Later, SyncNow does not ask again for that version, but the dot stays until you install it. When you are up to date, the Updates page says SyncNow is up to date and when it Last checked, with a Check for updates button and the Automatic checks box. At the bottom of the page, Installed version shows the version that is running, its signed release number and, when known, the day it was installed (pointing at the version shows its build date), and What's new, beside it on a wide window, lists the notes of that version.
Check for updates says Checking… while it asks; then either No new version — checked just now appears next to it, or the page shows the new version; after errors, checks pause for a while and the button says when you can try again. Automatic checks follows your account: the choice is kept on the SyncNow server and is the same on every PC where you sign in. Unticking it stops the checks while SyncNow is open, but SyncNow always checks once when it starts, and a mandatory update installs by itself, without asking. Agents connected to SyncNow normally reconnect on their own after the restart; an agent whose tools still come from the previous version is told to reconnect SyncNow in its AI client (in Claude Code, /mcp) to get the new ones, and if a new version fails on your PC, SyncNow goes back to the previous one: see How do I know an update is genuine, and what if a new version fails?.