The NIROS manuals contain details of all operating system updates since the previous manual; including updates to BASIC, and details of new or updated hardware. Once something has been described it will not usually be covered again in subsequent manuals unless a relevant change has been made, so to get a complete picture of the 8870 you really need all the NIROS manuals including the revision manuals.
It wasn’t until somebody contacted me out-the-blue and said they had a copy of this manual that I knew version 3.2 even existed. There was a lot of effort required to translate the operating system from German to English so in the UK, not every version of NIROS was released. If it was felt there may be technical issues or it didn’t contain anything of use to the UK market then the release would be ignored.