The update_scheduled_task description said every optional schedule field
left out of an update keeps its stored value. Only timeZone, webhook dedupe
and filters do; a left-out signature turns off signature checks and left-out
weekdays make the task daily. The description now says which fields to
resend.

A client whose time zone data lacked a zone the server had accepted refused
every edit to that task. The web and mobile forms now leave an unchanged zone
out of the save, so the server keeps it, and still refuse a newly typed
unknown zone.

The user guide said a skipped time runs an hour later; it runs later by the
size of the clock change, which is 30 minutes on Lord Howe Island.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>