Learnpress 3.0 + WP 4.9 – works!
But courses curriculum didn’t migrate couse of error in php code.
Problem solved when I changed build_curriculum() function:
$sections_units_quizzes = $wpdb->get_results("
SELECT section_id, section_name as id, 0 as orderid
FROM {$wpdb->prefix}learnpress_sections
WHERE section_course_id = $course_id
GROUP BY section_id
UNION ALL
SELECT section_id, item_id, 1
FROM {$wpdb->prefix}learnpress_section_items
WHERE section_id IN (SELECT section_id
FROM wp_learnpress_sections
WHERE section_course_id = $course_id)
ORDER BY section_id, orderid
");