Introduction
It started with a single support ticket at 2:00 AM: "My class schedule is off by one hour on my iPhone." By 8:00 AM, the Registrar's office was flooded. Over 1,100 students were reporting missed classes, incorrect exam times, and total calendar chaos. The culprit wasn't the students or their phones. It was a legacy SIS export that ignored RFC 5545.
The Technical Failure: "Floating Time"
Floating Time occurs when a timestamp lacks a timezone definition (`Z` or `TZID`). The reading device (iPhone, Outlook) interprets the time based on its own local settings, leading to massive drift during Daylight Saving Time.
Most legacy Student Information Systems export calendar data in "Floating Time." They assume that if a class is at 09:00, it is simply `DTSTART:20240901T090000`.
When 1,142 students synchronized their schedules, their phones guessed the timezone. Students in the same dorm room saw different class times depending on whether their phone was set to `America/New_York` or `UTC`.
How We Diagnosed the Issue
The Registrar sent us a sample `.ics` file from their Ellucian Banner calendar export. We ran it through our validator and immediately spotted the problem: zero VTIMEZONE blocks.
Every `DTSTART` was floating. No `TZID` parameter. No fallback `Z` suffix. Just raw timestamps that iOS and Android interpreted differently.
We pulled the access logs. Over 1,100 unique device IDs had fetched the feed in the past 24 hours. The error wasn't isolated. It was systemic.
Why Banner Exports Floating Time
Ellucian Banner was built in 2004, when most calendar clients were desktop-only (Outlook 2003, Lotus Notes). Back then, "floating time" was acceptable because users manually set their system timezone once.
But in 2024, students use iPhones that auto-switch timezones when traveling. A student flying home for Thanksgiving would see their Monday 9 AM class shift to 6 AM Pacific Time because the phone reinterpreted the floating timestamp.
Banner never updated its export logic. Many universities using legacy SIS systems face this exact issue.
The Solution: VTIMEZONE Injection
We didn't touch the university's Banner database. Modifying a 20-year-old SIS is risky and slow. Instead, we deployed a Zero-Persistence Proxy in front of the feed.
As the ICS stream passed through Lokr, our engine detected the missing `VTIMEZONE` component. It immediately injected a strict, calculated timezone definition block matching the university's physical location.
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Lokr Calendar API//Repaired//EN
X-LOKR-REPAIRED: fixes=vtimezone-injected-America/New_York|injected-prodid;client=1142
BEGIN:VTIMEZONE
TZID:America/New_York
BEGIN:STANDARD
DTSTART:20231105T020000
RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:20240310T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240901T090000
DTEND;TZID=America/New_York:20240901T100000
SUMMARY:Introduction to Computer Science
UID:banner-cs101-fall2024@university.edu
DTSTAMP:20240815T120000Z
X-LOKR-REPAIRED: fixes=vtimezone-injected-America/New_York|injected-prodid;client=1142
END:VEVENT
END:VCALENDAR
What Changed
The proxy runs at the edge. Every request is repaired in real-time. No caching. No batch jobs. No database writes.
The Result: Silence
Within 200 milliseconds of deployment, the feed was corrected.
1,142 errors vanished instantly as devices refreshed.
Zero code changes were made to the university's servers.
The Registrar's support queue dropped to zero calendar tickets within 24 hours.
Infrastructure shouldn't be a guessing game. If your student body relies on their phones, your feed must rely on standards.
Ready to silence your support queue?
More universities are trusting Lokr to fix Banner and PeopleSoft feeds instantly.
Audit Your SIS FeedConclusion
Legacy systems will always exist, but they don't have to break the student experience. By treating calendar data as critical infrastructure, we bridge the gap between 2004 databases and 2024 devices.
Want to see if your feed has the same issue? Validate your ICS structure or activate a 14-day trial to see the fix in action.