MySQL Ver. 5.7 Time Zone New Variable log_timestamps

You can see new system varable log_timestamps in MySQL Ver. 5.7. It introduced MySQL Ver. 5.7.2 .

[log_timestamps] 

log_timestamps controls the timestamp time zone of error log, general query log and slow query log's time information.
You can set log_timestamps at runtime.
Value type is enumeration ( 'SYSTEM'.'UTC') .
Value format is YYYY-MM-DDhh:mm:ss.uuuuuu + z signifying Zulu time (UTC) or + hh:mm ( offset from UTC)

[Warnning]
If MySQL startup with --timezone to mysqld_safe, No effect log_timestamps.
You should use default-time-zone system variable instead of --timezone to mysqld_safe.