Canada modernizing her River-class frigates according to the Australia Station Intelligence Summary dated 1 February 1955

An item reported that 16 of the 21 River-class frigates of the Royal Canadian Navy were converted to the HMCS Prestonian standard which would be completed by March 1955. Of the 16 ships were 11 to be commissioned and 5 placed in reserve at Sydney, Nova Scotia. The remaning five were early 1956 to be completed and then added to the reserve.

Source

Website Royal Australian Navy, Sea Power Centre.