Set default PHPFPM time zone to UTC. Use the work flow below when developing application to deal with time. In an ideal situation server will never need to convert time from UTC to any other time zone. All conversion logic will be handled by client side JavaScript.
User posting comment
Use UTC time on server as comment create or update time.
Transfer UTC time from database to viewer's browser and use JavaScript to convert UTC time to user's local time.
User is entering time in form
On form submission, convert user's submitted time to UTC and store the value in a hidden field.
Server will use the time from hidden field instead from actual date-time field.
Set default PHPFPM time zone to UTC. Use the work flow below when developing application to deal with time. In an ideal situation server will never need to convert time from UTC to any other time zone. All conversion logic will be handled by client side JavaScript.
User posting comment
User is entering time in form