In the mean time though I've been catching up with the series with these amazing two short story collections.
The first book contains two short stories which have previously been published on their own. Brayan's Gold follows Arlen on his first run as an apprentice messenger alone on a frozen mountainside hunted by a giant rock demon and in The Great Bazaar of Krasia he and Abban work to get hold of maps of a long lost city. These two are #1.5 and #1.6 in the series, and requires you've read the first book to recognise characters, plot and settings.
The second book, Messenger's Legacy, is a bit different. It's book #3.5 in the series, and Brett explains in the introduction that the first chapter of it was meant as the opening chapter of the third book, but the story grew and had a mind of it's own. It's the story of the child Briar Damaj, a half-Krasian, living with his family in Bogton, who flees into the night when tragedy strikes. It's a story that features the Messenger Ragen rather than Arlen himself. Brett also writes in his introduction to look for Briar making appearances in the 4th book, The Skull Throne.
On their own these books are not 5 star books. More like 4 stars. But the thing is - these books are not on their own. They stand tightly interlaced with the other books in the series and might as well have been in them. They are more like chapters cut out because of lack of room rather than individual short stories. And such - as a whole - they are every bit as good as the other 3 books published so far - and every single one of those were 5 star reads, and so are these two.