Also, when 5 was announced the state of extensions support was uncertain (I finally got the Delicious add-on back working again without compatibility fiddling and definitely didn't want to mess with it).
Having said that, the unrealistic and bureaucratic IT policies of backwards companies are their problem and not for open source to solve (are they donating?). If they're so concerned maybe they should hire someone to contribute to the project full-time so they can stay abreast of changes and maybe have a say in the direction of development.