Emacs 25 is the latest version, released September 17, 2016.
Where to get
Major changes
Gtk's Xwidget integration: watch youtube inside Emacs
Better built-in eww, web browser
Experimental Cairo integration
Load external shared libraries
New unicode characters input method
New library: Project (as a subset of Projectile)
Better history of query-replace
Package.el improvements
New library: seq.el and map.el (replaces dash.el)
New library: xref, to replace tags, etags, xctags
Others
Dired: auto-revert buffer on file change
Json, tramp, and more
See also
Versioning of Emacs