Last Modified: Oct 07, 2026
Affected Product(s):
BIG-IP TMOS
Known Affected Versions:
21.1.0.1, 21.1.0.2
Opened: Sep 22, 2026 Severity: 3-Major
BIG-IP ships tzdata 2018e, so DST rules that have changed since 2018 are wrong. America/Edmonton still shows DST transitions in 2026, even though Alberta has moved to permanent MST (ABT)
Local timestamps and time-based scheduling can be off by one hour during affected DST windows
Any BIG-IP build with tzdata-2018e-3 using a zone whose IANA rules changed after 2018e, notably Alberta and recent BC updates
Set timezone to UTC until fixed
None