You will find all the Chorus VDSL details here

https://sp.chorus.co.nz/product/vdsl/resources

Since they rolled out VDSL Vectoring and Diagnosis Driven Dynamic Line Management in 2017 there has been no product changes to VDSL.

There are unlikely to be any product changes in the short to medium term. Even long term I see this as unlikely. 

They are rolling out a few new cabinets in rural areas, there removing many of them in urban areas and the uptake and footprint of VDSL is shrinking as people move to fibre.