We just released Mastodon 4.5.4, 4.4.11, 4.3.17 and 4.2.29.
These versions contain various bug fixes, including a high and a moderate severity security fixes.
Mastodon v4.2.29 will be the last update for the Mastodon v4.2 branch, please update to newer versions as soon as you can.
Full release notes and update instructions are available on the GitHub releases page.