Did some digging. Euro 5+ apparently has the same emission limits as Euro 5, but adds more self-diagnosis and system durability requirements. You know how your car has oxygen sensors both before and after the catalyst? That's what they'll have to do. (Plus all the underlying software changes to implement the self-testing, plus the wiring harness and ECU I/O for the extra sensor.) Up until now, the catalyst-monitoring requirements that cars have had for a long time, haven't been required, so there has only been an oxygen sensor before the catalyst and the system had no knowledge of whether the catalyst was working (or existed at all). Means anything Euro 5+ should have a post-catalyst sensor in addition to the normal one before the catalyst.
It's supposed to take effect in 2024 (i.e. already in effect) for models new to the market, and models currently in production can remain in production as-is until 1 Jan 2025.
Means 2024 will be the last model year for the R1, and probably quite a few other models, in the EU market. Some other manufacturers (notably Suzuki) have kept selling bikes in North America after discontinuing them in Europe, because North American motorcycle emission standards are antiquated.