Re: @Drefsab_UK - Good
Why?
Your supplier/vendor in the supply chain will have to fix it- they wont until they have to.
OR your teams that you are supporting who are using the old protocols are not re-enginerring themselves to the vendor/suppliers new product - usually because its 'inconvenient' (which is often wrapped in 'its not possible').
OR your policy says that connection to X for purpose Y must be encrypted (usually for some external compliance piece like PCI) and now it is being exposed that it isnt, so you need to find a 'better' solution.
Use IE11 if you are stuck - keep Firefox for the day to day stuff.