Posted by Sharon
2018-05-27

Currently php 5.3 (can go up to 5.6)
Posted by Tom
2018-05-27

Hi,

>Currently php 5.3 (can go up to 5.6)

The error seems to appear in PHP 5.3 of a certain Linux distribution (Maybe Ubuntu?).

I think your problem is the same as this one.

Warning: strtotime() – PHP 5.3 and Joomla!
https://www.gavick.com/blog/warning-strtotime-means-small-problems-with-php-53-and-joomla

If you can upgrade your PHP to 5.6, go ahead. Most likely it disappears.
If you have to stay with 5.3, then set up date.timezone as described in the link shown above.