You can reach the Teclast site simply typing teclast.com and change the Chinese to English (upper line). For my Tbook 10 the last firmware(?) is dated September ’16 (identical code with the July release, though…).
Thanks for letting me know – I didn’t realise this.
But checking the drivers available for download for the E5A6, I see it’s about 250 MB altogether. Seeing that Double Driver extracted 593 MB of drivers from my tablet – and they all look like system drivers – I’m not inspired by confidence!