Yes, ALL public sector pensions will now be indexed to CPI not RPI.
Includes those already being paid.
It really is a change in terms & conditions but reference to "index linking" does not state specifically which index and so legally, if not morally, they can use any index they like.
In some penison documents a reference to indexing to "retail prices" is not even sufficient to hold them to RPI since the CPI is also based on some retail prices.
This change hits past, present and future members of HM Forces, their dependants and widows harder than any other sector of society.
As another poster put it recently "We just got mugged".