I know it's been a while since the 4th book finished, but I have some good news. The 5th John Taylor story is finished and going through the last rounds of editing now. I expect it to start posting either Aug. 31st or Sept. 5th, depending on the number of revisions it has to go through.
I'll post up more information later this week when I have a better idea of how long it will take. Stay tuned (Here, my author website, or twitter will all have the info).