Now using 2.4.1 without apparent issue, however, during the database upgrade it held on an error. After this, it allowed me to continue and I can't find any apparent problems with the Moodle. Please tell me if I need to address this urgently.
Sorry the formatting got lost in the following debug info:
Debug info: Error code: codingerror Stack trace: line 563 of /cache/stores/file/lib.php: coding_exception thrown line 382 of /cache/stores/file/lib.php: call to cachestore_file->ensure_path_exists() line 493 of /cache/classes/loaders.php: call to cachestore_file->set() line 1230 of /cache/classes/loaders.php: call to cache->set() line 6632 of /lib/moodlelib.php: call to cache_application->set() line 6699 of /lib/moodlelib.php: call to core_string_manager->load_component_strings() line 7391 of /lib/moodlelib.php: call to core_string_manager->get_string() line 1354 of /lib/upgradelib.php: call to get_string() line 496 of /lib/upgradelib.php: call to print_upgrade_part_end() line 1544 of /lib/upgradelib.php:call to upgrade_plugins() line 349 of /admin/index.php: call to upgrade_noncore()
As always, I am loving this community - also feel free to tell me: go get get a developer, you nincompoop ;)