Bel,
The insurance company cannot force you do an update but, they can deny you & make you look for new insurance. The fuses themselves will be around for a while, but, the fuse boxes have not been manufactured for a long, long time, and if you have a problem with the box, it probably, will cost you more being it could end up being an emergency repair. ( the story of my life) You would likely have to have the entire service upgraded and this would involve the power company as well. If your service is that old, chances are so is the wiring maybe, time for a rewire, because the insulation could be degraded due mostly, to age. Even if the conductors in your wiring are doing their job, it doesn't mean the insulation is, too. Some companies won't even write an insurance policy if your home has a fuse box or, Knob & Tube wiring. We ran into this a long time ago in our first house.