Short answer is you need to be up to code for fire stuff.
Long answer is you are at risk of being taken advantage of by “fire consultants” who are also in the business of providing fire upgrades or get kick backs from referring strata’s to particular companies.
We went through something similar in Sydney, small old building. A couple of fire companies quoted upwards of $100k to bring the building up to current code (ie: all the bells and whistles as per a new build).
However some fairly close scrutiny on what the actual minimum requirements were (on top of what was already there) brought this down to around $12k – which was upgrading one of the pumps and connecting smoke detectors to a back-to-base monitoring service.