Due to delays in the missile development, the missile was substituted with the short range P-70 Ametist (SS-N-7 Starbright) submerged launch missile which itself was a development of the P-15 Termit (SS-N-2 Styx) surface-launched missile.
The P-15M was fitted with an L band sensor and a new altimeter radar both developed for the 'Siren', but there was no room for a datalink in the smaller 'Styx'.
India is NPO's second largest customer after Russia for sale of P-70 Ametist, BrahMos, P-800 Oniks and possibly the P-500 Bazalt