Steps to reproduce the issue

1 - Set up a Joomla 3.8.7 site using mod_random_image to display random images in a location on the home page.
2 - Upgrade to Joomla 3.8.8.

Expected result

Site still works with no changes.

Actual result

Site crashes with error "Using $this when not in object context". Debug reveals that the problem is mod_random_image. Disabling mod_random_image results in site working again (although, obviously, the random image is now missing).

System information (as much as possible)

Linux 16.04.4 LTS
PHP 7.0.30
Apache 2.4.18
MySQL 5.7.22

Additional comments

I have not tested a fresh installation so I am unclear if the problem is with mod_random_image or the upgrade package. Either way, as mod_random_image is bundled with Joomla, my view is that a fixed version needs to be released ASAP.