Hi Lifemark,

Thank you for reporting the time zone changes.

The case is escalated and we'll do our best to provide support for them soon.

Until kendo.timezones.js is updated in an official release, you can patch the affected zones after loading kendo.timezones.js and before initializing the Scheduler. The patch keeps the existing DST history and switches each zone to a fixed offset from the date of its change, so events created before the change are not shifted.

(function () {
    var changes = {
        "America/Vancouver": [Date.UTC(2026, 2, 9), 420, "MST"],
        "America/Edmonton": [Date.UTC(2026, 5, 18), 360, "CST"],
        "America/Winnipeg": [Date.UTC(2026, 9, 31), 300, "EST"],
        "America/Inuvik": [Date.UTC(2026, 7, 21), 360, "CST"]
    };

    Object.keys(changes).forEach(function (name) {
        var zone = kendo.timezone.zones[name];
        var change = changes[name];
        var last = zone[zone.length - 1];

        if (last[1] !== "Canada") {
            return;
        }

        zone[zone.length - 1] = [last[0], last[1], last[2], change[0]];
        zone.push([String(change[1]), "-", change[2]]);
    });
})();

The values are offsets in minutes (positive is west of UTC), taken from tzdata 2026f. The patch can stay after kendo.timezones.js is updated, because it skips zones that no longer end with the Canada rule.

Here is demonstration of the workaround: https://dojo.telerik.com/JFUxsfuK. 

Alternative: you can use Etc/GMT+5, Etc/GMT+6 or Etc/GMT+7 (fixed UTC-05, UTC-06, UTC-07). This is simpler, but it replaces the zone for all dates, so the historical times of existing events recorded during DST will shift by one hour.

Regards,
Rumen
Progress Telerik