Sorry to be vague but went to lecture about future of the various IRs, now there are different versions to be had. Apparently "RNAV" becomes more important and that means all the newfangled GPS boxes. As ILS is closed down, more RNAV approaches will become availabe, and mandated by 2024. But meanwhile, skill tests for IR (R) probably in 2018 will need to be done in aircraft approved with RNAV. Not sure if that will effect renewals same way, but if it does, it will make mine more difficult/expensive.
And then after next year RNAV theory becomes part of the test. This info comes from PPL/IR Europe. You could probably find more on
www.pplir.org.
Sorry it's not more comprehensive, but it's probably worth researching.