Moodle 3.3. Theme Boost
Editing course settings doesn't allow saving the settings.

Moodle 3.3 and Clean
Settings are saved but several problems in Debug mode visible

pix_url is deprecated. Use image_url for images and pix_icon for icons.

• line 267 of /lib/outputrenderers.php: call to debugging()
• line 554 of /course/format/grid/renderer.php: call to renderer_base->pix_url()
• line 315 of /course/format/grid/renderer.php: call to format_grid_renderer->make_block_topic0()
• line 176 of /course/format/grid/format.php: call to format_grid_renderer->print_multiple_section_page()
• line 280 of /course/view.php: call to require()