Foss alternatives generally handle this by either not changing the format too much or by making old versions available to download in perpetuity and then you can manually upgrade your decades old library at your leisure. I'm really glad they don't spend their already limited resources on trying to handle every possible old library file under the sun, as long as you've got incremental upgrades working you've got a path. And if you are not using it on timescales that would allow for incremental upgrades you are not the ICP anyway so they've made a good engineering decision.