source: Mozilla makes Firefox 60 next ESR target - gHacks Tech News
Mozilla plans to make Firefox 60 the next ESR (Extended Support Release) version of the Firefox web browser, and not Firefox 59.
New major Firefox versions are released every six to eight weeks. Mozilla introduced a fixed six week rapid release cycle back in 2011, but switched to a flexible 6-8 week release cycle in 2016.
The organization introduced Firefox ESR specifically for organizations to increase the time between major releases. Firefox ESR is available for organizations and home users. While ESR versions of Firefox do get security and bug fix updates whenever a new major version of Firefox is released, feature updates are only introduced after several release cycles.
The next major Firefox ESR update was scheduled to be Firefox 59, but it appears that Mozilla will postpone the move to Firefox 60.
Note: Plans may change. We will update the article if changes to the schedule are announced.