Prerequisites
- Create an App Password — The credential device sync needs
What Your Device Can and Cannot Change
Device sync works both ways, within the limits of who owns what.
What It Is
Device sync lets a change made on your phone or laptop reach Zyntro. That is true of your own calendar without qualification: create, edit, move or delete, and Zyntro follows.
Your calendar also shows meetings you were invited to but did not organise — a colleague's meeting that you are attending appears on your calendar too. Those are a different case. The meeting belongs to whoever organised it, so your device cannot rewrite its time, title or location, and cannot delete it.
What you can do from your device is answer it. Accepting or declining a meeting there records your answer in Zyntro, exactly as answering the emailed invitation would.
Why It Matters
Because one calendar shows two kinds of entry and they are not equally yours. The meetings you run and the meetings you attend sit side by side on the same screen, and nothing about how they look says which is which.
Because a change that cannot be made should say so. Before October 2026 an edit to someone else's meeting from a device appeared to succeed and was then quietly discarded. Your phone showed the new time, Zyntro kept the old one, and nothing told you the two no longer agreed. Your calendar app now reports an error instead, which is less convenient and considerably more honest.
Because your answer is worth recording wherever you give it. Accepting a meeting on your phone used to change nothing in Zyntro. Now it does, so the organiser sees your answer however you gave it.
How It Works
Your own events. Anything on a calendar you own is fully editable from a synced device, in both directions, including repeating events.
Meetings you were invited to. Your device may record your answer — accepted, declined or tentative. It may not change the meeting itself, and it may not delete it. An attempt to do either is refused, and your calendar app will show whatever error it shows for a change the server would not take.
Declining is not deleting. Removing a meeting from your phone does not cancel it, because it was never yours to cancel. Decline it instead: the organiser is told, and the meeting stays on their calendar where it belongs.
Your answer and the organiser's are kept apart. Answering from your device records your answer only. It cannot change what anyone else on the meeting said, even if your calendar app happens to show their answers alongside yours.
Examples
You drag one of your own bookings an hour later on your phone
It moves in Zyntro, and the attendee is notified with a calendar update, exactly as if you had moved it in Zyntro yourself.
You try to shorten a colleague's meeting from your laptop
The change is refused and your calendar app reports an error. The meeting is your colleague's to change — ask them, or decline and propose another time.
You accept a colleague's meeting on your phone
Your answer is recorded in Zyntro and shows as Accepted beside your name on the meeting, and the organiser is notified.
You delete a meeting you were invited to, to clear your week
The deletion is refused, because deleting it would remove it for the organiser and everyone else. Decline it instead, which tells the organiser you are not coming and leaves their meeting intact.
Tip: If a change on your device is refused, check who organised the meeting. That is the usual reason. The meeting's own page in Zyntro names the host, and anything you did not organise is theirs to change.
