The ULB upgrade consists of replacing the battery, in the existing (30 days) ULB, with a new Li Ion battery to support 90 days ULB operation. There is one ULB attached to the cockpit voice recorder and one ULB attached to the flight data recorder.
Your needs
As the ULB has its own battery and the physical dimensions are identical no mechanical or electrical changes have to be performed but the replacement of the ULB(s). Furthermore a ULB has to be attached to the data link recorder if the aircraft needs to have one due to operational requirements. There are several requirements in the Air Operations Regulation demanding the 90 days ULB (CAT.IDE.A.XXX, NCC.IDE.A.XXX and SPO.IDE.A.XXX).
Your benefits
No mechanical or electrical change is needed.
The new equipment is identical in shape and weight. Therefore no change is necessary to the recorders attachments. The existing 30 days ULB is self-powered as well as the newly installed 90 days ULB.