Fatal error: Call to undefined function request_filesystem_credentials()

[ruud@…]

Hi,

In our errorlogs something peculiar showed up which I like to mention here:

Call to undefined function request_filesystem_credentials() in /*/*/*/.*.*/htdocs/wp/wp-admin/includes/class-wp-upgrader-skin.php on line 93

In this timeframe the site in question was trying to auto-update from either 4.9.2 to 4.9.3 or from 4.9.3 to 4.9.4.
I'm not sure which is was exactly however I do know it performed an separate auto-update to 4.9.3 prior to one to 4.9.4

Besides this website the logs show several more websites with similar fatal errors happening from [06-Feb-2018 19:48:01 UTC] till [07-Feb-2018 02:05:05 UTC]

Thanks,
Ruud

[ocean90]

Duplicate of #43235.

See also ​https://wordpress.org/news/2018/02/wordpress-4-9-4-maintenance-release/.