  The NA48/2 Collaboration at CERN has accumulated and analysed unprecedented
statistics of rare kaon decays in the $K_{e4}$ modes: $K_{e4}(+-)$ ($K^\pm \to
\pi^+ \pi^- e^\pm \nu$) and $K_{e4}(00)$ ($K^\pm \to \pi^0 \pi^0 e^\pm \nu$)
with nearly one percent background contamination. It leads to the improved
measurement of branching fractions and detailed form factor studies. New final
results from the analysis of 381 $K^\pm \to \pi^\pm \gamma \gamma$ rare decay
candidates collected by the NA48/2 and NA62 experiments at CERN are presented.
The results include a decay rate measurement and fits to Chiral Perturbation
Theory (ChPT) description.
