Changes to the print_header API and use of $PAGE are breaking the questionnaire module. Viewing a questionnaire gives the error:

This page did no call $PAGE->set_url(...). Relaying on a guess.

    * line 338 of /lib/pagelib.php: call to debugging()
    * line 450 of /lib/pagelib.php: call to moodle_page->get_url()
    * line 1364 of /lib/blocklib.php: call to moodle_page->__get()
    * line 857 of /lib/blocklib.php: call to block_add_block_ui()
    * line 312 of /lib/blocklib.php: call to block_manager->ensure_content_created()
    * line 833 of /lib/outputrenderers.php: call to block_manager->region_has_content()
    * line 707 of /lib/outputrenderers.php: call to moodle_core_renderer->handle_legacy_theme()
    * line 1879 of /lib/outputrenderers.php: call to moodle_core_renderer->header()
    * line 185 of /lib/setuplib.php: call to moodle_core_renderer->fatal_error()
    * line ? of unknownfile: call to default_exception_handler()

...and...

Coding error detected, it must be fixed by a programmer: The $meta parameter to print_header is no longer supported. You should be able to do everything you want with $PAGE->requires and other such mechanisms.