if that's the best they have they're roughly 71 years behind in nuclear technology
their nuclear capacity has nearly tripled since the program began, so this is concerning news no matter how small the yield
not to mention their advances in rocketry and miniaturization
The US yielded 15 MEGAtonnes in 1954, they are nowhere near today's capability.
ivy mike was a hydrogen bomb, so the comparison isn't entirely equivalent
I do agree that they're far behind today's capability, though