The IBM Redbook titled IBM i Technical Overview with Technology Refresh was updated on September 12, as it approaches its planned publishing date of October 31 2014. The Redbook covers last year’s Technology Refresh 6 and 7 (TR6 and TR 7). You can download it here. It is a big book of 952 pages.
I thought it would be useful to accompany this with IBM i chief architect Steve Will's overview of these Techincal Refreshes.
Technology Refresh 8 (TR8) for IBM i 7.1 was released in April 2014, and I am hearing that Technology Refresh 9 (TR9) is "coming soon". We will have to wait for a Redbook about them.