Privacy

Here is an overview of all audits done on Signal:
https://community.signalusers.org/t/overview-of-third-party-security-audits/13243
No recent server audits really. They are pretty public about information requests made by the government and their responses though, and from what I can see the only pieces of information they have shared with the government to this point are the time of account creation and the date of the last connection to Signal servers:

You can check more of their responses from here:
https://signal.org/bigbrother/