That's Jinke's official firmware. Jinke is the company that produces the HanLin V3, Astak is only a rebranding of Jinke's e-reader. And Jinke is a chinese company.
This is their official download page. Go to the part that reads "下载名称： V3升级程序V2.11", and, despite it being in chinese, you'll see that the description mentions the same three letters acronyms that keng2000 reported. Also, if you click on the blu link you'll see that the download link points to the same file that keng2000 linked.
So yes, it's official.
You may notice that in the english section of Jinke's website there isn't a link to this firmware, but it's not the first time that the english version of the site gets updated slower.