Found a way to make it work on Volla:
In the patch file there is given the file name:
/usr/share/jolla-calendar/pages/EventEditPage.qml
Opened folder using CLI as devel-su and made a backup copy.
Opened EventEditPage.qml with vi command. Scrolled down until I found this:
//% "Remind me"
label: qsTrId("calendar-add-remind_me")
menu: ContextMenu {
Repeater {
id: reminderValues
model: [-1 // ReminderNone
, 0 // ReminderTime
, 5 * 60 // Reminder5Min
, 15 * 60 // Reminder15Min
, 30 * 60 // Reminder30Min
, 60 * 60 // Reminder1Hour
, 2 * 60 * 60 // Reminder2Hour
, 3 * 60 * 60 // Reminder6Hour
, 12 * 60 * 60 // Reminder12Hour
, 24 * 60 * 60 // Reminder1Day
, 2 * 24 * 60 * 60 // Reminder2Day
]
delegate: ReminderMenuItem { seconds: modelData }
(sorry, can’t tell what line number because vi didn’t show the line numbers)
Changed the 6 in the line of the 6h reminder into 3, (ignored the comment Reminder&Hours, no change there) and saved, then rebooted the GUI by Sailfish Utilities.
In fact I can now create a calendar entry and get the option for Alarm 3 hours before including the right labelling. Will now set a test event and then report if alarm really sounds 3h before.
edit: Test succeeded.