Another backward incompatible change, not mentioned in the docs, is that function `date_default_timezone_get()` no longer returns current time zone.
Prior to 8.2, this function returned:
- Time zone set by `date_default_timezone_set()` (if set).
- Time zone specified in `date.timezone` (if set).
- Current time zone, if none of above applies.
From 8.2 onward, if neither of the first two variants applies, this function returns UTC. This breaks scenarios where current time zone shall be used.
See <https://github.com/php/php-src/issues/11496> for discussion.