I'm sorry if this is the wrong forum, but there seems to be nothing else which seems to fit better. I have developed an iOS App which supports Firefox Sync since about 10 years, so users of my App can directly access their firefox bookmarks. Within these years it seems that Firefox Sync has deprecated the BrowserID authentication method (which I didn't noticed because everthing worked fine) but only since recently the relevant API call "certificate/sign" is no longer working, so the authentication process will fail. Therefore I'm looking for information how exactly I can implement the authentication now. Unfortunytely it is very hard to find reliable API documentation. Most API docs that are found seem to be heavily outdated and still list the no longer valid "certificate/sign" API call. Even the docs which already mention that Browser ID will be canceled in the future are also already outdated and half of the links lead to 404 pages. So I would like to ask the following: Is there any definite valid up-to-date API specification for Firefox Sync and its authentication process available (suitable for third-party Apps which can not rely on Firefoxs own internal frameworks and code), and where exactly can I find it. And if a need to register an app ID/client ID and secret to be able to authenticate the App, how and where can I do this? Can anyone point me to the right direction? Thanks for all the help...