For those sticking to Firefox Extended Support Releases, the Firefox 60 branch will be the next ESR version.

Firefox 60 will be an ESR release and the plan is to have the ESR 60.0 release out on 8 May, the Firefox 60.1 ESR release on 3 July, and to end Firefox 52 ESR on 28 August when releasing Firefox 60.2.

With this Firefox 60 ESR release they are also introducing Policy Engine as a new feature for enterprise users to offer more configuration/customization support. The Firefox Policy Engine through a configuration file will allow enterprise administrators to easily block domains, control pop-ups and plugins, handle default bookmarks, and control other behavior of the browser for systems.

Those wishing to learn more about the Firefox 60 Extended Support Release plans can do so at the Mozilla.org blog.