Half hour time zones missing

Question

In PHP I am using DateTimeZone::listIdentifiers() to get a list of time zones for user selection. This seems to be working fine, but missing from this list are

Answer 1

Just guessing here, but it looks like the default $what parameter is DateTimeZone::ALL, and you want to use identifiers that only exist now for backwards compatibility - so you should use DateTimeZone::ALL_WITH_BC:

print_r(DateTimeZone::listIdentifiers(DateTimeZone::ALL_WITH_BC));

Note that the manual does say not to use them.

In the case of Iran, you could replace it with the Asia/Tehran time zone for example.