Plugin update causes PHP notice and server time advance

Hello Rolf,

I had posted a few minutes ago on another thread, didn’t realise that it was marked resolved.

I tried to update the plugin on a new site late last night and it failed with white screen, citing possible permission issues. I finally succeeded, but found inexplicable code in the new WP installation core files, so feared it had been attacked, during the installation although Wordfence had found nothing. I reinstalled WP and your plugin and all seemed OK.

Today I installed on 4 localhost severs and 6 hosted servers with the message:
Notice: date_default_timezone_set(): Timezone ID ” is invalid in \wp-content\plugins\rvg-optimize-database\rvg-optimize-database.php on line 84.

I discovered that on some, including the one yesterday, it had changed the server time by +7 hours. The difference being that, if a city is used to set the timezone, this time advance occurs, but if the manual UTC time is used it does not change the time. This may provide a pointer.