To upgrade your existing Bolt 3.x installation, run

composer update

Released: 2021-06-08. Notable changes:

• Notify users of 4.0 stable release. #7890
• Improve Yaml export for compatibility with Bolt 4/5 Conimex import. #7910
• Killing PHP7.4.3 exceptions post-migration from older Bolt/PHP versions. #7906
• Fix: Fetching content by Taxonomy does not work if ContentType Name is different than ContentType Slug. #7894
• Allow rel-attribute by default. #7885
• Allow {{ fields(record = record) }}, to pass in a record not in global scope. #7912
• Add Composer 2 compatibility. #7913
• Fix: querying by ContentType slug (fixes regression introduced in #7894) #7916