Version 155 of the Firefox web browser has been released. Notable changes include a count in the address bar of how many ad trackers Firefox has blocked, container reordering, and ensuring that mailto: links are only opened by explicit user actions. There is also a change of the domain used for "captive portals" (such as the ones used to sign into hotel WiFI): Firefox now uses "firefox-portal-detection.com" instead of "detectportal.firefox.com", which may require a change in network allow lists. The release also includes a number of changes that may impact web developers, as well as a number of bug fixes and security fixes.