As you may know, OpenWrt is a Linux based operating system for routers, simulating a powerful OS present on modern and expensive routers.
The latest version available is OpenWrt 15.05.1, which updates the main components. Among others, it adopted Kernel 3.18.23, OpenSSL 1.0.2f, Samba 3.6 netifd, uhttpd, rpcd, uci, procd, ubox, and hostapd.
Some restart issues have been removed, a bunch of video card drivers have been updated and support for some routers have been added, including: Linksys WRT1900ACS (mvebu), LinkIt Smart7688 (ramips), TP-LINK TL-WR841N/ND v10 (ar71xx), D-LINK DIR-615 rev. Ix (ar71xx), ZBT WG2626 (ramips), and Linksys WRT1900ACS (mvebu).