If it was me, I wouldn't have completely ditched the old system. If they're currently on 5.0, instead of moving to 2409 and potentially having a huge problem if they ever went back on the plan (think Windows 3.1 -> 95 -> 98 -> 2000 -> 7 -> 10), they could have just called it 5.2409 instead. If they had a genuine semantics breaking change or major new feature that they're really proud of, they could then bump it to 6.yymm.