@MK Correct. OWRT 19 was really not much more than a kernel and toolchain upgrade. OWRT 20 was never officially released. OWRT 21 included a load of networking changes so it was the most logical to change up to but then OWRT 22 came along pretty quickly and fixed the 2038 date issue and upgraded firewall technology so it was nice step forward. Alas it broke the GPIO numbering so many of us needed to rejig things and that takes time. Hence 23 is the logical step forward. The custom firmware build I use is mainly to debloat things and add in my own software and configuration, I try to stay as close as possible to the Onion build.