The Firefox 188.8.131.52 has not been officially released yet but they have all of the files available on their FTP. All of the links that need to be ready for the release have been made available and now it is just a matter of them updating the Firefox homepage. Here are the available downloads for the English version:
The release notes have also been posted which states that this release fixes some stability and security issues. If you are currently running Firefox 184.108.40.206 you shouldn’t have to worry about downloading the new version because it will eventually update itself over the next few days.