A quick and simple replacement for the deprecated function strftime can be following.

Instead of using (taking the sample from the question)

$date = strftime("%e %B %Y", strtotime('2010-01-08'))

convert that to:

$date = date('d M Y', strtotime('2010-01-08')

The strftime is obsolete and DateTime::format() provide a quick replacement and IntlDateFormatter::format() provied a more sophisticated slution.

this links will be help you:

https://github.com/modxcms/revolution/issues/15864

https://github.com/php/php-src/blob/1cf4fb739f7a4fa8404a4c0958f13d04eae519d4/UPGRADING#L379-L381

https://www.php.net/manual/en/datetime.format.php

Hey I have also experienced this issue as well so after some research on PHP's official documentation here what I found! https://www.php.net/manual/en/function.strftime.php
They are saying that it is depricated and use setlocale() function this also work same as strftime().
For more information please visit official PHP docs of setlocale() https://www.php.net/manual/en/function.setlocale.php