The name of that particular class hasn’t, but lots of other things changed.
What are you running from cron and how are you calling it? I use it for boring stuff like scheduling posts without problems - are you doing something more esoteric?
For some things we don’t use Wordpress’ cron infrastructure because we need a bit more control. Therefore we call a PHP script from a Linux cron, like this:
cd /path/to/wp-content/themes/ourtheme/
/usr/bin/php7.0 -f cronjobs.php do=do_some_stuff
And this triggers the error. It worked with older versions of WP fail2ban.
For this cronjobs.php we actually do not need WP fail2ban. So, if we find a way to disable it for this specific call, the problem will be solved.
OK, I’ve worked out what’s going on - I’ll fix it in 4.3.0.5.
The problem is that you’re running a script from a directory containing a file called functions.php, and PHP is loading that one instead of the one in WPf2b.
As it’s a simple fix I’m hoping to have the release done later tonight.